The Pittsburgh Steelers had a busy free agency, including the signing of cornerback Levi Wallace, and today I wanted to provide some data context to what he provided last season in coverage along with Pittsburgh’s cornerbacks as well. Let’s get right to it, starting with 2021 coverage snaps and targets to get a gauge of the quantity of plays comparatively.
Comparing Wallace’s 2021 opportunities in Buffalo to the NFL and Steelers, we can see he was utilized at an above the mean rate of the 100 players on the graph. His 551 coverage snaps tied for 20th in the NFL, with his 60 targets tying for 38th most with three other players including Cameron Sutton. The latter had the most coverage snaps of the players we’re focused on, with 606 which was the 11th most in the NFL. The remaining Steelers were below the mean in opportunities, important context as we continue with the data.
Now let’s begin to examine the quality of play with completion percentage and deserved catch percentage, which is the number of completions and drops divided by the number of catchable targets and passes defensed.
Impressively, Ahkello Witherspoon landed alone at the top right of the graph with the top ranks in the NFL, with a low completion percentage of only 29% (over 8% better than the second rank) along with a deserved catch percentage of 52.9%. It is extremely important to remember this was on one of the lowest sample sizes of the group of players, but very encouraging nonetheless with an expected role increase this season. Levi Wallace was the only other player above the mean player in our sites today, with the 31st rank in completion percentage (51.7%) along with a deserved catch percentage of 75.6% that tied for 36th.
Haden tied for 39th (53.7%) in completion percentage but was below the mean deserved catch percentage at 80% (tied for 65th). Pierre tied for the 44th completion percentage rank with two other players at 55% with his 85.2% deserved catch percentage ranking much lower at 86th. Sutton landed below the mean in both data points with a completion percentage of 63.3% that ranked 85th, and an especially low deserved catch percentage of 88.9% which was 95th out of 100 players!
This made me wonder if the results were correlated to coverage scheme, so here are man vs. zone percentages from PFF for more context:
| PLAYER | MAN% | ZONE% |
| Ahkello Witherspoon | 39.3 | 44.9 |
| Levi Wallace | 33.3 | 52.2 |
| Cameron Sutton | 28.6 | 56.4 |
| James Pierre | 28.4 | 57.1 |
| Joe Haden | 27 | 58.3 |
So, the stronger completion results favored players who played man coverage at a higher rate as expected. The high completion percentages allowed by Sutton were partially due to spending more time in zone, but important context is added considering Haden and Pierre played zone at higher rate with better completion results.
Next, let’s look at the depth of targets with yards per attempt and yards per game:
Wallace fared very well tying for the second rank in yards per coverage snap at 0.5 yards along with the fifth rank in yards per attempt at only five yards, which is impressive considering his above the mean usage. Witherspoon and Haden were the 2021 Steelers that landed above the mean in both data points. The former had a yards per attempt number of 6.1 that tied for the 22nd rank, but lands lower than the latter in the results when factoring his snap counts. Sutton was at the mean in yards per coverage snap, adding positive context to his yards per attempt number of nine that ranked 93rd. Pierre was well below average in both regards, tied for the fourth most yards per coverage snap, important context to his yards per attempt number that bested Sutton.
Another stat that is used often to evaluate defenders in coverage is QBR Against, so let’s see how they fare along with Wins Above Replacement (WAR) which is a points above replacement scale conversion that is based on the scoring environment.
Witherspoon fared well with another top NFL rank in QBR against (23.5) along with tying for 10th in WAR. Wallace is the other player above the mean in both data points, with a 61.9 QBR against which ranked 14th along with a WAR result that tied for 33rd. Sutton had mixed results faring well in WAR (T-17th) but a QBR against of 106.3 that ranked 87th. Haden and Pierre landed below the mean in both, with the former landing at a WAR number of zero along with a QBR against of 91.9 (T-66th). Pierre was the only player in our sights with a negative WAR result along with a stronger result than Haden in QBR against of 88.1 that tied for the 52nd rank.
To close, let’s look at Boom and Bust percentages from SIS to see how the players fared against big plays:
- Boom % = The percentage of dropbacks that resulted in an EPA of 1 or more (a very successful play for the offense)
- Bust % = The percentage of dropbacks that resulted in an EPA of -1 of less (a very unsuccessful play for the offense)
Encouragingly, the three expected primary corners for 2022 land on the top right of the graph. Witherspoon tops another ranking here in bust percentage, meaning he provided the highest percentage of very unsuccessful plays when in coverage. His boom percentage also ranked high at 14th respectively. Sutton’s bust percentage ranked 10th along with a lower result in boom percentage that tied for 35th. Wallace’s boom percentage was stronger with a rank that tied for 17th, but a lower bust percentage that ranked 36th. So, when comparing Sutton and Wallace, the former provided a higher rate of very unsuccessful plays while the latter limited big offensive plays. Pierre and Haden land below the mean again as they did on the previous graph. Pierre’s was near the mean in bust percentage, while Haden fared better in boom percentage.
In regards to the data and outlook for 2022, we can see that Wallace was encouragingly above average in every aspect of today’s study. Another key takeaway was he also landed above Haden (no longer with the team) in all the data, and here’s to hoping he can provide that value in Pittsburgh, likely in the starting lineup with his experience primarily on the boundary and his quality of play. Witherspoon provided great results with top NFL ranks in completion percentages, QBR against, and bust percentage along with above average results in yards per attempt and snap, WAR, and boom percentages on a small sample size last season. Sutton fared best in usage, WAR, and boom/bust percentages along with an average result in yards per coverage snap, but was below average in completion percentages, yards per attempt, and QBR against. Pierre was below average in every aspect of the data except for completion percentage. While there are unanswered questions like how Wallace will perform in the black and gold, how will Witherspoon fare with an increased workload, and how will the rotation/alignments look with Sutton and others, I am optimistic for a strong 2022 season from the unit.
What are your thoughts on the data? Thanks for reading and let me know your thoughts in the comments!
