2017 Passing Plus-Minus

by Scott Kacsmar

For the fourth time in the last decade, the NFL's single-season record for completion percentage was broken. For the third time it was Drew Brees setting a new benchmark, after he already did so in 2009 (70.62 percent) and 2011 (71.23 percent) for the Saints. Sam Bradford's record of 71.56 percent for the 2016 Vikings lasted just one season as Brees finished 2017 with a mark of 72.01 percent. For comparison, it has taken much longer for other single-season passing records to reset four times despite this last decade being such a pass-happy climate. The last four resets for passer rating span from 1989 (Joe Montana) to 2011 (Aaron Rodgers). Touchdown pass records span from 1984 (Dan Marino) to 2013 (Peyton Manning), while yardage marks span from 1981 (Dan Fouts) to 2013 (Peyton Manning).

League-wide completion percentage had been consistently improving to record rates. The previous four seasons (2013-2016) each set a new record, but 2017 was a step backwards, with the average rate declining from 63.0 percent to 62.1 percent. There were a lot of significant quarterback injuries in 2017. Still, 2017 was the fourth-highest season on record, so it does bring into question just how impressive the record that Brees keeps breaking really is in this era.

One of the stats we annually track to help provide context to completion percentage is passing plus-minus. In case you forgot, passing plus-minus estimates how many passes a quarterback completed above or below what an average quarterback would have completed, given the location of those passes. It does not consider passes listed as "Thrown Away," "Tipped at Line," or "Quarterback Hit in Motion." Player performance is compared to a historical base­line of how often a pass is completed based on the pass distance, the distance required for a first down, and whether the ball was thrown to the left, middle, or right side of the field. Note that plus-minus is not scaled to a player's total attempts.

2017 Passing Plus-Minus

These results are for the 35 qualified passers from 2017 with at least 200 pass attempts. Note that rookies Deshaun Watson and C.J. Beathard are included here despite showing 195 passes each. Again, the total number of passes will differ from the NFL total due to the removal of certain passes. To help express plus-minus as a rate stat, "C%+" is also included. Numbers will be expressed with a + or - sign.

Brees really owns passing plus-minus in a way few players have ever owned a stat before. This is the sixth time he has led all quarterbacks in passing plus-minus since 2010. His +37.9 mark would rank as the eighth-highest season since 2006. A big part of why Brees has dominated this stat is that he combines pinpoint accuracy with a high volume of production on a yearly basis, but he still easily had the highest C%+ by any quarterback in 2017 too. Also, 2017 was the first time Brees attempted fewer than 600 passes since the 2009 season. He still managed to lead the league in completions (386) and yards per attempt (8.1) in an interesting year that saw him adopt much more of a shorter-passing attack.

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In fact, Brees attempted the shortest passes (average depth of target: 6.6 yards) of any quarterback in 2017. The Saints targeted running backs on 34 percent of their passes, the highest rate by any offense since 2007. We also charted the Saints with the lowest rate of dropped passes (3.4 percent), which helps his numbers as well. That's not to say Brees just dinked and dunked his way to these league-leading numbers. On passes thrown more than 10 yards downfield, Brees still led all quarterbacks in plus-minus with +18.6.

Passing DVOA leader Case Keenum was a distant runner-up to Brees in both plus-minus and C%+, but it's still a shock to think how well 2017 went for the sixth-year journeyman. In his previous seasons, Keenum was always a negative passer in plus-minus, accumulating -27.6 prior to joining the Vikings last year. We'll see if he can bring any of his new success to Denver. Meanwhile, Kirk Cousins is filling in for the Vikings and is coming off a season where he was just +7.7. That's a far cry from the previous two years where Cousins was +27.1 (2016) and +25.0 (2015), but he also dealt with a lot of injuries and changes to his supporting cast last year. The Vikings should offer the type of high-end receiving duo Cousins can flourish with in Stefon Diggs and Adam Thielen, and we'll see on Thursday just what type of impact those two had on Keenum's numbers when we look at receiving plus-minus.

At age 40, Tom Brady won the MVP, and his +19.9 was his highest season mark since 2011 (+20.4). He adjusted well to a more vertical passing game with Brandin Cooks and without an injured Julian Edelman. Alex Smith also had some surprising results last year with a career-high +19.5, topping his previous best of +16.0 with San Francisco in 2012, the year he was injured and lost his job to Colin Kaepernick. Now we'll see if Smith can build on last year's success in new surroundings after he was traded to Washington.

It was a weird season, but Jameis Winston (+18.7) and Josh McCown (+16.8) ranking in the top six is up there with Keenum on the weirdness scale. It also shows some of the value of this stat. Winston was only 12th in conventional completion percentage (63.8 percent), but that doesn't account for the fact that he is one of the most vertical passers in the game. His average depth of target in this study came at 10.7 yards, second only to Watson (10.9). In fact, each year Winston's passes get a little deeper, but he has done a great job of improving his plus-minus. He has gone from -14.5 as a 2015 rookie to +3.2 in 2016 to a similarly big increase in 2017. As for McCown, he was actually fourth in completion percentage (67.3 percent) and 2017 was arguably his best season yet given the preseason expectations for the Jets. Remember, many pegged this team to go 0-16 and wondered how they would score touchdowns, but McCown did a really respectable job at 38 years old. His previous best season was +10.3 for Marc Trestman's Bears in 2013.

Most of the old guard takes up the top 13 spots, but the young guns who should shape the next decade of the league are tightly bunched together after that. We are referring to Dak Prescott (+4.4), Marcus Mariota (+3.2), Deshaun Watson (+2.9), Jared Goff (+2.8), and Carson Wentz (-3.5). Goff's placement relative to his offense's success is still pretty average, and we will see part of why that is next week when we look at YAC+. However, it's still a massive improvement over his rookie season when he was -18.8 on just 186 passes.

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Wentz has had two minus seasons so far, but he is similar to Cam Newton in playing style. The fantastic throw after a scramble is always a possibility, but so is the overthrow on a routine play. Newton was -16.8 after two years, but did improve to +6.2 in his 2013 season. That, however, is still his best season, and one of only two years where Newton was a plus passer. He's actually -64.9 for his career, which is the third-lowest mark in the NFL since 2011, better than only Blake Bortles (-69.3) and Blaine Gabbert (-65.7). Derek Carr (-48.5) is next on that list above Newton; he has never done better than -7.5 (2016) in a season. We'll see if Jon Gruden's return to the game can do anything for Carr this year.

Sometimes the coach can really help, but often it comes down to the player himself. We may have seen a great example of that in San Francisco last season. Brian Hoyer and C.J. Beathard both produced poor numbers in running Kyle Shanahan's offense. Once Jimmy Garoppolo took over after his trade from New England, the offense was suddenly productive. Garoppolo finished at +7.1 in his limited action, which would have placed him 13th, or above Aaron Rodgers on the table. Garoppolo's C%+ was 4.1 percent, a rate that would have ranked fifth in 2017. A full season of Garoppolo in San Francisco is definitely one of the most intriguing storylines heading into 2018.

As for the bottom of the table, it is probably fitting that we have the quarterbacks from the teams with the first and second picks in the 2018 draft. The Browns knew they had to do better than DeShone Kizer, who had an abysmal rookie season, and this draft was too rich in quarterbacks to pass up someone like Baker Mayfield. We thought the Giants might sense the same thing with an aging Eli Manning, but alas they went the running back route with Saquon Barkley. Manning's plus-minus has been dropping each season since 2014, and he's down to -44.5 in the last three years. Consistent accuracy has never been a strength for the younger Manning brother, but at 37 years old, he doesn't have youth on his side anymore either.