Rams, 49ers Attack Each Other's Weaknesses

NFL Conference Championship - Kyle Shanahan owns Sean McVay. Perhaps you have heard. Since the two head coaches were hired in 2017, Shanahan's 49ers are 7-3 against McVay's Rams, both straight up and against the spread. They've done this despite being underdogs in eight of those 10 games. They've won the last six in a row against the Rams. Now on Sunday, Shanahan's 49ers will meet McVay's Rams in the postseason for the first time.

Back in Week 10, the 49ers demolished the Rams on Monday Night Football by a final score of 31-10. The score was closer in Week 18, when the 49ers had to win in order to make the playoffs. San Francisco pulled off a win in overtime, 27-24. According to DVOA, the game was not as close as the final score. The 49ers gained 6.7 yards per play compared to 4.1 yards per play for the Rams and ended with an 88% Post-Game Win Expectancy despite the need for overtime.

The 49ers really are built to attack the weaknesses of the Los Angeles Rams defense. It's a big reason they keep winning games against them. But there are ways in which the Rams are built to attack the weaknesses of the San Francisco 49ers defense as well. The Rams were still the better team during the regular season and they've been the better team in recent weeks, even accounting for their losses to the 49ers. Can they finally pull off a victory against their rivals from northern California? Or will the 49ers complete the three-game sweep?

For those curious, this is the fourth time where a team has swept a division opponent during the regular season but then gone into the playoff rematch as an underdog:

• The Rams swept the Seahawks in 2004 but were +4 underdogs. They won outright.
• The Titans swept the Jaguars in 1999 but were +7 underdogs. They won outright.
• The Seahawks swept the Raiders in 1983 but were +7 underdogs. They lost, 30-14.

The Rams may have home-field advantage in this game, but it's probably not going to feel like home-field advantage. When the 49ers played in Los Angeles in Week 18, the stands felt very split between Rams and 49ers fans.

If you are unfamiliar with the Football Outsiders stats, they are explained at the bottom of the page. Scroll down or click this link. Game charting data appears courtesy Sports Info Solutions, unless noted. All stats represent regular season only, except for weighted DVOA and anything else specifically noted.

All readers can click here for the open in-game discussion thread.

If you have FO+, you can click here to see all the matchup of DVOA splits for this game.

WHEN THE 49ERS HAVE THE BALL

As you can see from the week-to-week graphics, the 49ers' offense has not been at its best in the postseason, but otherwise the passing game had picked up in the second half of the season. San Francisco's pass offense DVOA had gone from 24.8% DVOA in Weeks 1-9 (11th) to 42.5% DVOA in Weeks 10-18 (second). Meanwhile, the Rams' defense has been better in the second half of the year with two particularly strong games in the playoffs. But the Rams' two worst games in defensive DVOA since midseason happen to be the two games against San Francisco.

You probably know the conventional wisdom by now. The Rams defense plays a lot with two high safeties, giving up runs and throws underneath as a trade-off to prevent big pass plays downfield. This is true in some ways, not true in others. Given that conventional wisdom, you might be surprised at my first piece of advice for the 49ers offense: spread the Rams out.

The Rams are not known for the strength of their off-ball linebackers, so it will surprise you to learn that they were a significantly better defense when they had more linebackers and fewer defensive backs on the field. Overall, NFL offenses average 5.2 yards per play against base defense (four defensive backs), 5.7 yards against nickel, and 6.2 yards against dime. But when the Rams put their defense on the field, the gap between base defense and dime defense was 2.5 yards per play, not 1.0 yards. And in the two games against San Francisco, the differences were even more extreme.

Turn things around and look specifically at the 49ers offense against various defensive personnel groupings, and you'll find the same splits. The 49ers had positive DVOA against each defensive personnel grouping, but the difference between the 49ers and the league average was bigger against nickel than base and even larger when opponents were in dime.

The 49ers uses more 21 personnel than any other offense in the league, but I really don't think that's the way to go to beat the Rams. You want to get into 11 personnel and then run from that. Yes, that probably means a lot of Deebo Samuel running the ball. Here are some more interesting numbers, now looking at it from the perspective of the 49ers' personnel groups. It's interesting to note that the 49ers gained more yards per play from 21 personnel both rushing and passing, but had higher DVOA from 11 personnel both rushing and passing because of the down-distance situations and which opponents were faced more often by each personnel group.

Theoretically, part of the idea here is to make the Rams bring more defensive backs on the field, which usually leads to fewer men in the box, which makes running the ball easier. And in fact, the Rams do use the league's lowest average number of men in the box according to SIS charting: 5.96 on average each play, compared to the NFL average of 6.48. This has nothing to do with facing specifically pass-oriented down-and-distances. Even on just first-and-10, the Rams used an average of 6.07 men in the box, once again the lowest in the NFL with a league average of 6.60.

But this actually might not be part of the reason why the 49ers have been successful against the Rams. While teams in general are better running against lighter boxes, the 49ers were not this year.

It's interesting to note that the down/play splits match for the 49ers offense and Rams defense. Both rank fifth in the league on first-down runs. Both the 49ers offense (third) and Rams defense (second) excel on second-down runs. And both the 49ers offense (23rd) and Rams defense (28th) are then much weaker on third-down runs.

As far as where the 49ers should run, adjusted line yards numbers suggest the 49ers are much better running to the left than the right. The Rams have much stronger run defense against wide runs than against inside runs: first against runs left end and second against runs right end but 20th against left tackle runs and 13th against middle runs.

But the 49ers did not beat the Rams twice this year by running all over them. Sure, they had 156 yards rushing in the first game in Week 10, but that was because they took a big early lead and then just ran clock through the second half. In Week 10, the 49ers had their best passing day of the year by DVOA, but their run offense DVOA was about their average for the year. Things were more balanced in the Week 18, with both run and pass DVOA beating San Francisco's averages for the season.

So let's talk about that passing game. This is where the San Francisco offense really attacks the weakness of the Rams defense. The Rams rank second in the NFL against deep passes (16 or more air yards) but 22nd against short passes including 29th against short middle passes. The issue here is catch rate, not YAC. The Rams allow a slightly above-average YAC on short middle passes (the Rams allow a slightly above-average YAC on pretty much all passes) but also allow an 83% catch rate on these passes, the highest in the league.

And San Francisco? The 49ers throw a league-high 28.4% of passes into the short middle and rank fourth in DVOA on those passes. San Francisco's numbers on short middle passes in the first two games: 18-of-21, 10.1 yards per pass, and a 62% success rate. They don't throw a lot of deep passes, where the Rams defense excels. In the two playoff games, Garoppolo has only thrown the ball over 15 air yards three times.

The strength of the 49ers' passing game is that the receivers break a lot of tackles and earn a lot of yards after the catch. Overall, San Francisco broke tackles on 11.7% of plays according to SIS, fourth in the league. Deebo Samuel led all wide receivers with 37 broken tackles or that George Kittle was second among tight ends with 20. The Rams are roughly average as a tackling defense. Their defenders with the most broken tackles are linebacker Troy Reeder (15), edge rusher Leonard Floyd (11), and safety Nick Scott (10 despite only 23 solo tackles during the regular season).

It won't shock you when I tell you that the cornerback coverage stats suggest to stay away from Jalen Ramsey and go after third cornerback David Long Jr. Ramsey allowed just 4.9 yards per pass this year, compared to 6.4 yards per pass for Darious Williams and 8.5 yards per pass for Long. Long is not necessarily in the slot when the Rams are in nickel or dime; in fact, Ramsey (who moves all around in the "Star" position) will play a lot of snaps in the slot. In the first two games, it looked like the 49ers tried to get Ramsey lined up on Samuel but it confuses things when Samuel moves into the backfield.

The Rams were about average in general against wide receivers this year, and 24th in DVOA against running backs in the passing game. But the Rams were also fourth covering tight ends. They held Kittle to just 10 yards on 5-of-7 passes in the Week 18 game. It was mostly zone coverage, with different defenders on each pass. The scheme shut down Kittle more than one specific defender.

The place where the Rams defense really has it over the 49ers is when it comes to the pass rush. By a number of metrics, the Rams' pass rush is outstanding and the 49ers' pass blocking is very pedestrian. For example, the Rams rank first in ESPN's pass block win rate, led by Aaron Donald who is on a different planet than other defensive tackles in ESPN's pass-rushing stats. The Rams are also third in pressure rate and eighth in adjusted sack rate. The 49ers rank 18th in pass block win rate, 13th in presssure rate, and 17th in adjusted sack rate.

The weakness of the 49ers' offensive line is on the right side. Right guard Daniel Brunskill led the 49ers in blown blocks. Right tackle Tom Compton only started half the season but was second on the team in blown pass blocks. Pass block win rate has Brunskill 49th among 63 qualifying guards and Compton 51st among 68 qualifying tackles. By comparison, left tackle Trent Williams ranks ninth and left guard Laken Tomlinson is 14th. If the Rams move Donald to the left edge at all and have him going up against Brunskill or Compton, it could be brutal.

The trick to getting pressure on Garoppolo is to pressure him with just four pass-rushers. Garoppolo had a strange split this year. He was the second-best quarterback in the league when blitzed, according to ESPN QBR. He was also horrendous under pressure. Garoppolo averaged just 3.0 net yards per play when pressured and 2.1 net yards per play when pressured by just four pass-rushers. Both figures were near the bottom of the league. The 49ers will pick up your blitzes, but get to Garoppolo with four pass-rushers and he does not do well at all.

The Rams were roughly league-average in the frequency with which they blitzed. Incidentally, Garoppolo was not particularly good when the Rams blitzed him in the first two games. He averaged just 4.3 net yards per pass. There was a 40-yard touchdown to Deebo Samuel late in the Week 10 game, but only two other first downs out of 14 passes. But overall for the entire season, Garoppolo was fantastic against the blitz.

Finally, I usually don't think quarter or half splits mean too much, so file this under "head-scratching and maybe interesting." The Rams defense this year was worse after halftime and much worse in the fourth quarter. The Rams defense was No. 2 in the first half this season, but 13th in the third quarter and 29th in the fourth quarter. However, the poor fourth-quarter defense generally came when they were either winning or losing by a large amount. The Rams were much better when games were close after halftime: third in defensive DVOA in "late and close" situations.

WHEN THE RAMS HAVE THE BALL

The Rams' passing game was better in the first half of the season, but has rebounded with strong performances in the playoffs. Meanwhile, the 49ers defense has been gradually improving throughout the entire year and put up two of its best performances so far in the playoffs.

The Rams had a very good offense this season, even accounting for the decline in the second half of the year They finished the regular season in the top 10 of offensive DVOA for every down/play combination except third-down rushing, where they were dead last. That's going to be a problem for the Rams if they get into third-and-short situations; the Rams ranked 29th with a 54% success rate on short-yardage runs. San Francisco's run defense, meanwhile, ranked second overall in defensive adjusted line yards and 12th on short-yardage runs with a 66% success rate allowed. And there won't be many fourth-down runs. Sean McVay may be on the cutting edge of a lot of things in the NFL but not fourth-down decisions. McVay ranked 31st out of 34 head coaches in Aggressiveness Index on fourth downs this year. Kyle Shanahan isn't much better, ranking 27th.

We keep pointing this out in these previews, but the 49ers were very weak during the regular season against deep passes: 31st in the league. The Rams threw an above-average number of those deep passes during the regular season but ranked only 13th in DVOA on deep passes. In the first two games, Rams were 6-of-12 on deep passes for 178 yards. Matthew Stafford threw three picks on deep passes but they were VERY deep: 42, 49, and 51 yards.

The 49ers ranked fifth in DVOA covering tight ends this season and fourth covering running backs. They were 26th covering wide receivers, and to be more specific, they were 31st covering No. 1 wide receivers. Cooper Kupp had 122 and 118 yards in two games against the 49ers plus drew a DPI flag in each game. (As for tight ends, Tyler Higbee did go 6-of-8, 55 yards in the Week 18 game but was only 3-of-5, 20 yards in the Week 10 game.)

The 49ers cornerback coverage stats are led by Emmanuel Moseley, who was significantly better than his teammates this season.

K'Waun Williams is the nickelback and is generally covering the slot. The other starter opposite Moseley is up in the air. Josh Norman has been mostly benched at this point. Ambry Thomas took over as a starter in Week 11 and while he was burned deep often in his first few games, he played better over the last couple games of the season, including the interception of an overtime pass to Odell Beckham that sealed San Francisco's Week 18 win. He missed last week's game with a bone bruise in his knee and Dontae Johnson took his place.

The battle in the trenches is much closer on this side of the ball, at least in the passing game. Stafford does not take a lot of pressure, as the Rams were the third-lowest team in pressure rate. The Rams also ranked first in pass block win rate and seventh in adjusted sack rate. The 49ers defense ranked ninth in pressure rate, fifth in pass rush win rate, and fifth in adjusted sack rate.

The Rams offensive line really shines on the edges. Andrew Whitworth and Rob Havenstein are third and fifth in pass block win rate. (Whitworth has been out since the first play of the wild-card game with knee and ankle injuries but is on track to return against the 49ers.) However, the interior can be a problem for the Rams. Austin Corbett is 51st and David Edwards 37th among guards in pass block win rate with Brian Allen 24th among centers. Corbett and Allen also led the Rams in SIS's count of blown blocks. Look for pass pressure from the 49ers' interior line, with Arik Armstead and the always underrated D.J. Jones.

Remember how I wrote above that Jimmy Garoppolo was the second-best quarterback in the league this year when blitzed, according to ESPN QBR? Well, the best quarterback in the league when blitzed was Matthew Stafford, with a fabulous 92.3 QBR. It's a good thing for the 49ers that they were near the bottom of the league in blitz frequency. This is a strong contrast to the two teams the Rams had to beat to get here, Arizona and Tampa Bay, who are at the top of the league for blitz frequency.

According to SIS, the 49ers blitzed Stafford 10 times in the first two games and he averaged 9.3 net yards per pass (including a 7-yard DPI gain) with just one sack and one incomplete pass. Both of his touchdown passes to Tyler Higbee in Week 18 came on blitzes in the red zone.

Yet Stafford also had the same strange dichotomy that Garoppolo had: fantastic against the blitz but horrible against pressure overall. Stafford averaged just 3.1 net yards per play when pressured and 2.5 net yards per play when pressured by just four pass-rushers. Both figures were near the bottom of the league and very similar to the numbers for Garoppolo. If the 49ers can get past the Rams' offensive line and bring pressure with just four pass-rushers, they should knock Stafford off his game.

Stafford also had interesting splits against man and zone coverage this season. He averaged 8.23 yards per pass with an 18:3 touchdown to interception ratio against man coverage, but 7.67 yards per pass with a 12:12 touchdown to interception ratio against zone coverage. The 49ers mixed zone and man coverage this year, but were a little lower than the NFL average in how often they used man coverage and a little higher using zone coverage.

The Rams do like to run the ball, and this is a matchup of strength against even more strength. The 49ers run defense was the best in the league over the second half of the season. As noted above, they finished the season second in adjusted line yards. In particular, the 49ers are strong at stopping runs where the Rams like to run. The Rams love their wide runs, ranking fifth in ALY left end and first right end. But the 49ers are also sixth against runs left end and first against runs right end.

Cam Akers' early return from an Achilles injury showed an admirable work ethic but it's worth asking if it was really the best thing for the Los Angeles Rams. Darrell Henderson was the running back for most of the year and finished with 10.2% rushing DVOA. Sony Michel played a lot as well, particularly after Henderson got hurt, and finished with 0.7% rushing DVOA. In two playoff games with 41 carries, Akers has an abysmal -54.9% rushing DVOA. He's averaging 2.5 yards per carry. Yes, he's much more useful as a receiver than Michel is, but as noted above, that's not a weakness of this 49ers defense. When the Rams want to run the ball -- although they really should concentrate on passing instead of rushing against this defense -- it's probably better for them to bring in Michel.

SPECIAL TEAMS

TThe Rams have an advantage in the third phase but their strengths don't really match the 49ers' weaknesses. The 49ers were particularly weak this year on kickoffs and kick returns, two areas of special teams where the Rams didn't particularly excel. The Rams were best on field goals and punt returns, the latter because of Brandon Powell who took over the job near the end of the season. Since he took over in Week 15, including the playoffs, Powell is averaging an astonishing 19.3 yards per punt return. However, the 49ers ranked fifth in net punt value during the regular season, the best part of their special teams unit. They allowed only two returns all year longer than Powell's average. One of them was... to Brandon Powell, a 31-yard return when these teams played in Week 18.

The other area where the Rams' special teams really excelled was on field goals and extra points, as Matt Gay ranked third in the NFL in value behind Justin Tucker and Chris Boswell while San Francisco's Robbie Gould was average. However, given the general inconsistency of field goal kickers and Gould's quality career numbers, it's hard to say that this is really an area of advantage for the Rams. Both teams should be able to trust their kickers if it comes down to a late field goal, at least as much as you can trust a kicker who isn't named Justin Tucker.

OUTLOOK

The concentration on San Francisco's matchup advantages does sort of undersell the quality of the Los Angeles Rams offense this year. The fact is, the Rams offense was very, very good and the 49ers defense was not as good over the course of the entire season. It's hard to cover Kupp, Odell Beckham, Van Jefferson, and Tyler Higbee, all at the same time. But it's easier if you can bring pressure with just four pass-rushers, and the 49ers can do that. That pressure makes up for their weakness on the back end.

On the other side of the ball, the 49ers really are built to attack where the Rams are weakest. When judging two teams in a rematch, it is best to look at the entire season rather than focusing on what happened the first time (or two times) those teams played earlier in the year. The larger sample size tells you more information, and rematches don't always follow what happened in the earlier games. But looking at stats from the entire season... the 49ers really are built to attack where the Rams are weakest. They will attack the short middle of the field. They will run the ball from every formation and personnel group. They will use motion to make it hard for Jalen Ramsey to key on Deebo Samuel. It's not a good matchup for the Rams -- but if the Rams can bring enough pressure, they can turn the tables on the 49ers.

Overall, I think this game is very much a 50-50 matchup. The Rams may be the better team from the regular season and the last two weeks as well, but the advantages that San Francisco has will neutralize that difference. Even though the Rams are the favorites, this seems like anybody's ballgame, and a 49ers sweep and return to the Super Bowl is a very realistic scenario.

STATS EXPLAINED

DVOA (Defense-adjusted Value Over Average) breaks down each play of the season and compares it to the NFL average based on situation and opponent. You'll find it explained further here. Since DVOA measures ability to score, a negative DVOA indicates a better defense and worse offense, and a positive DVOA indicates a better offense and worse defense.

Team DVOA numbers incorporate all plays; since passing is generally more efficient than rushing, the average for passing is actually above 0% while the average for rushing is below 0%.

SPECIAL TEAMS numbers are different; they represent value in points of extra field position gained compared to NFL average. Field goal rating represents points scored compared to average kicker at same distances. All special teams numbers are adjusted by weather and altitude; the total is then translated into DVOA so it can be compared to offense and defense. Those numbers are explained here.

Each team is listed with DVOA for offense and defense, total along with rush and pass, and rank among the 32 teams in parentheses. (If the DVOA values are difficult to understand, it is easy to just look at the ranks.) We also list WEIGHTED DVOA (WEI DVOA), which is based on a formula which drops the value of games early in the season to get a better idea of how teams are playing now (explained here).

Each team also gets two charts showing their performance this year, game-by-game, according to offensive and defensive DVOA. In addition to a line showing each game, another line shows the team's trend for the season, using a rolling average of the last five games. Note that the defensive chart is reversed so upwards is a more negative defensive DVOA (which is better).