Odell Beckham Jr. had a season for the ages on the offensive side of the football this year and looks like an easy choice for Offensive Rookie of the Year, but two defensive rookies had rookie years that were equally as dominant. Oakland’s Khalil Mack and St. Louis’ Aaron Donald each ranked #1 at their respective positions, 4-3 outside linebacker and defensive tackle, on Pro Football Focus, the first defensive rookies to do so since Denver’s Von Miller did so at 4-3 outside linebacker in 2011. Other rookies had strong rookie campaigns in 2014, San Francisco’s Chris Borland, Baltimore’s CJ Mosley, and Minnesota’s Anthony Barr are names that come to mind, but to me, this award is between Mack and Donald as none of the other 3 even ranked in the top-3 at their respective positons.
Once you get down to Mack and Donald, it becomes a very tough choice. Both led their respective positions over some established All-Pro caliber veterans. Mack finished #1 right ahead of the aforementioned Von Miller, the first time Miller hasn’t been #1 at that position since he broke into the league in 2011, while Donald finished right ahead of Ndamukong Suh and Gerald McCoy, both of whom have been top-4 defensive tackles in each of the past 3 seasons.
Mack played a role very similar to the one that Von Miller has played in Denver for 4 years, playing 4-3 outside linebacker in base packages and becoming an edge rusher in sub packages. Mack only managed 4 sacks on the season on a 3-13 Raiders team, which ultimately might be the reason he doesn’t win this award, but his pass rush numbers were better than his sack totals as he also managed 10 hits and 40 hurries. That still means his pass rush productivity was significantly worse than Miller’s, as Miller had 15 sacks, 11 hits, and 47 hurries, giving him a pass rush productivity of 11.8, while Mack was at 9.1.
However, Miller had the luxury of playing with a lot of leads on a Peyton Manning quarterbacked team, giving him more easy pass rush situations, while Mack played on an Oakland team whose offense led by Derek Carr was the worst in the NFL in rate of moving the chains differential by a wide margin at 62.27%. Jacksonville was next worst at 64.55%. Oakland’s defense was actually competent this season, allowing opponents to move the chains at a 72.33% rate that was a middle of the pack 16th in the NFL, largely due to the play of Mack. That was despite the fact that of 13 Oakland defenders to play more than 400 snaps this season, only two of them graded out positively, Mack and veteran Justin Tuck, who was Pro Football Focus’ 17th ranked 4-3 defensive end. If that’s your best defensive teammate and your defense is still capable, you played pretty well, regardless of what the sack numbers say. Mack also was significantly better than Miller as a run stopper.
Donald had a different rookie year. He had more than double Mack’s sacks with 9, very impressive for an interior player. When you add in his 6 hits and 29 hurries, you get a pass rush productivity of 8.3, worse than Mack’s, but 8th best among defensive tackles. And Donald wasn’t playing with a bunch of leads either. The Rams finished better than the Raiders did at 6-10, but their offense finished 25th in the NFL, moving the chains at a 68.90%. The Rams’ defense was why they were able to win 6 games, as they finished 5th, allowing opponents to move the chains at a 70.28% rate.
Donald was a big part of that, not just rushing the passer, but also stopping the run surprisingly well for a player listed at 6-1 288 coming out of college. Along with ranking #1 at his position, he was the only defensive tackle to rank in the top-5 as both a pass rusher and against the run. However, unlike Mack, he had a lot more help around him. While just 2 of 13 Oakland defenders who played more than 400 snaps graded out positively this season, 8 of 14 St. Louis defenders did so, including Donald’s defensive line-mate Robert Quinn, who finished as Pro Football Focus’ 10th ranked 4-3 defensive end. Ultimately, it’s a borderline toss-up between these two. I won’t complain if either of them wins it, but since I have to pick one I’m going with Mack for doing what he did with almost no help around him. This is easily the closest award race though.