The 2016 NFL draft class has already made its mark on the NFL, with rookie quarterbacks Dak Prescott of the Dallas Cowboys and Carson Wentz of the Philadelphia Eagles leading their teams to the NFL's best record and wild-card contention, respectively. Both players currently rank among the top 15 quarterbacks in Pro Football Focus's grades — Prescott is 11th at 83.9 on PFF's 0-100 scale, and Wentz is 14th at 81.8 — and have arguably been less impressive than Prescott's teammate Ezekiel Elliott, who leads the NFL in rushing with 1,199 yards while also ranking as the No. 1 running back in PFF grades at 86.8.
But as good as all three of those players have been, there is an argument to be made that the best rookie in the NFL on a per-game basis resides on the defensive side of the ball: San Diego Chargers edge defender Joey Bosa.
Bosa, whose Chargers host the Bucs on Sunday, is playing at a level just a notch below Von Miller. As a rookie.
Coming out of Week 12, Bosa ranks fifth among all edge defenders in PFF grades, with an 89.8 that ranks just a couple of tenths shy of the 90.0 threshold that begins the "elite" player designation. This puts him just shy of league leaders Khalil Mack of the Raiders (92.6) and Von Miller of the Broncos (91.6) — two of the very best defensive players in the NFL.
The rate at which Bosa has been generating pressure on opposing quarterbacks has been pretty remarkable. PFF has a statistic called pass-rush productivity that measures how often a defensive player produces pressure on a per-snap basis, with extra weight given to sacks. Bosa ranks fifth among all edge defenders with a score of 14.6 on the strength of his 39 total pressures: five sacks, 10 hits and 24 hurries on 209 pass-rush snaps. That's roughly the equivalent of getting a QB pressure on one in every five pass-rush snaps, which is one of the best rates you'll ever see. (For comparison, Miller is at 17.4 percent this year.)
Bosa has helped turn around the Chargers' fortunes this season
Bosa's impact has been seen in more than just the stat sheet. In a league where passing continues to take on increased importance, edge rusher is arguably the second-most important position on the field after quarterback. The ability to apply pressure to opposing QBs is the great equalizer in today's NFL, with the average quarterback's passer rating dropping by 30 points when he is under pressure compared to a clean pocket.
• When under pressure this season, Tom Brady (the No. 1 QB in PFF grades) has earned a passer rating of 93.2
• When throwing from a clean pocket, Blake Bortles (No. 27) has earned a passer rating of 92.2.
That's why the Chargers' 4-3 record since Bosa made his NFL debut in Week 5 (an offseason holdout delayed his arrival by four games, during which time San Diego went 1-3) can't be dismissed as a mere coincidence. In those four wins, the Chargers forced their opposing QBs into the following PFF grades:
Week 12 Brock Osweiler, Houston: 48.8
Week 9 Marcus Mariota, Tennessee: 60.0
Week 7 Matt Ryan, Atlanta: 76.1
Week 6 Trevor Siemian, Denver: 43.0
Only Ryan ranked among the top half of NFL QBs in grades for that particular week, and Bosa averaged 6.25 pressures in those four outings, including three total sacks.
There's also the critical fact Bosa is far from a one-dimensional player. In fact, his balance is remarkable. He ranks fifth overall in edge defender grades, including fifth as a pass-rusher and fifth against the run. This isn't surprising given his track record in college — he ranked No. 1 in the nation in PFF's edge defender grades in 2014 and 2015, and in 2015 he ranked first as both a pass-rusher and a run-defender. (As a true sophomore in 2014, he ranked first as a pass-rusher but only third as a run-defender. Slacker.)
Bosa's case is as strong as any of the other top rookies, if not stronger.
If you're willing to isolate this discussion to evaluating each rookie on a per-game performance, stripping away positional value (obviously, Bosa's late start to the year limits his overall contributions, and it's hard to argue that any position player is more valuable than a top-15 quarterback in the NFL), Bosa has a very strong case for the claim of league's best rookie.
He is playing at the same level as the NFL's best players at his position, with several standout performances and without any of the major down games both Prescott (vs. the Eagles) and Wentz (vs. the Vikings and Seahawks) have fallen victim to so far this season.
The debate over "which rookie is best at his position?" is tightest between Bosa and Elliott, his former Ohio State teammate. While Bosa has a higher PFF grade, Elliott actually ranks No. 1 at his position group, and has stood out not just for his running ability but for his ability to hold his own in the passing game, which often can provide the toughest learning curve for a rookie running back. He owns the No. 1 rushing grade, No. 8 receiving grade and No. 19 pass-blocking grade among backs.
But whether it's fair or not to "punish" Elliott for running behind a fantastic Dallas offensive line, Elliott has clearly been placed in an ideal situation to succeed early in his career. The Cowboys — who host the Bucs on Dec. 18 — rank behind only the Raiders in run-blocking grades so far this season, while Elliott ranks tied for 19th of 45 qualifying backs in PFF's elusive rating metric, which measures how effective a back is independent of his blocking.
On 266 total touches (carries plus receptions) this season, Elliott has 37 broken tackles this season. On an identical 266 total touches, Arizona's David Johnson has broken 59.
Now, again, is it fair to take away from Elliott's accomplishments just because he's successfully taken advantage of the good blocking his line has provided him? (You don't have to break any tackles when running untouched to the end zone.) Of course not. And it's hard to argue with anyone making the claim he has been the league's best rookie this season.
But for all of those who wish to point out (rightfully so) that we haven't seen a rookie performance like this from a running back in some time, consider this: None of the league's top edge rushers produced as rookies at the level Bosa is currently. Not Miller, not Mack, not Chiefs OLB Justin Houston, not Texans DE J.J. Watt. Miller came the closest back in 2011 with a pass-rush productivity of 12.3 during his standout rookie season, but that's still off the 14.6 pace being set by Bosa currently.
All of it adds up to Bosa being the most impressive rookie in the NFL since he took the field in Week 5. The Chargers appear to have found a franchise cornerstone with the No. 3 overall pick.