There seems to be some optimism surrounding Marcus Williams, the undrafted rookie from North Dakota State, who has started the last four games for the Jets at cornerback. Personally I have been a bit skeptical. I have gotten the impression Williams is not getting burned deep mainly for two reasons. First he provides such a big cushion on many plays that it would be impossible to get over the top of him, but a completion is there underneath whenever the other team wants. Second the cornerback play across from him has been so suspect that teams haven't felt the need to attack him. Darrin Walls got a bit of buzz early in the year, but it turned out he probably wasn't sticking out because opponents had it so easy going against Antonio Allen.
I decided to take a look at some of Williams' numbers to get a broad indication of how well he is playing. None of these numbers will provide a perfect look, but they might tell us something.
According to Pro Football Focus, 118 corners have played at least a quarter of their teams' coverage snaps. Williams is giving up a reception every 7.8 snaps. That's only 19th best out of 118. He has been targeted 23 times and allowed 18 receptions, a very high 78.8% allowed. Opponents have only gained 158 yards, 8.8 yards per reception on him, 6.8 per target, and 1.13 per cover snap. The 1.13 per cover snap puts him at 43rd of 118. That isn't terrible, but again I wonder whether that is because teams are going harder after the guy on the other side. The big completion percentage suggests something will be there.
Even if it doesn't, the 158 yards he has allowed over 4 games projects to 632 over an entire season. That is typically in the bottom 30 to 40 of the league.
Williams isn't getting beaten to the degree other corners on the roster are, but I haven't seen a ton watching him to suggest he is going to be part of the solution at cornerback, and the numbers provide only modest praise of his play.