You can consider me a fan of San Francisco 49ers cornerback Dontae Johnson, or at least what he's capable of doing on the field. That said, I consider "Johnson the outside cornerback" and "Johnson the slot cornerback" to be entirely different players with vastly different skill sets and ceilings. That is to say, Johnson is an awful lot better on the outside than he is on the inside.
These are conclusions I've drawn from last season and his work thus far in the preseason. I think Johnson is great at turning and running with a receiver, and I think he does a good job at sticking to their routes and using his body for positioning when the ball is in the air. I also think Johnson isn't great at following a receiver across the middle of the field, and takes too long to develop his coverage and can be beaten by quick passes.
On Saturday against the Denver Broncos, we saw this in action. Johnson played the majority of his first couple drives on the outside and did not allow a reception. When he kicked inside, he had trouble adjusting and gave up a couple different plays. I went ahead and took two examples of the former and two examples of the latter for you good folk.
It's worth noting that the captures of him working on the outside weren't the only ones in which he found success, it's just two in which he was credited with covering the receiver who ultimately was thrown to. He looked good in coverage on other plays, but we don't have room to look at all of them.
Johnson has really good coverage on Demaryius Thomas on this play. Thomas turns his body and gets superior positioning, but Johnson gets his hand in there and even if Thomas plays that perfectly, Johnson looks like he swings in just the right way to knock the ball loose if he needs to. Ideally, Eric Reid is in a little bit better position given the amount of field the 49ers are working with, but I like Johnson in that matchup so long as it's on the outside.
On this play, Johnson takes his man deep, recognizes where Peyton Manning is going to throw it before he does throw it and steps up to make sure this pass wasn't complete. It wasn't a great throw and it might not have been complete otherwise, but Johnson makes the proper adjustment in time and ensures there was no chance of it being completed. I like his decisiveness, because he cuts to that receiver well before the ball is thrown.
This is what I was talking about with Johnson playing inside, he just doesn't close on his guys fast enough, especially when they're moving sideline to sideline. He just doesn't make that adjustment, and the Broncos picked up a very easy first down. That's the kind of play you expect a slower linebacker to be beaten by, not a starting cornerback.
Here's Johnson being beaten on a play that's very similar to the last. He doesn't do a good job sticking to the guy when he's playing the slot, even though the guy in the slot really isn't doing anything terribly impressive by any stretch of the imagination. That's not a dig -- he executes, and that's what the Broncos want, but Johnson gets beaten and gives up the first down on a play that a starting cornerback should be able to stop or at least limit the potential damage of in the best situation.
Now, this play includes Dontae Johnson but it's not really all his fault or anything like that. It's actually a fault of the entire defense, and of course on Manning being ridiculously good at throwing footballs. He drops that in perfectly over the linebackers' heads. It makes sense that Johnson gives some cushion because, from his angles, those linebackers have the play locked down if Manning tries to throw to that guy. But Manning is Manning, and he make fools of every single defense at one time or another.
Anyway, that's just a partial picture of Johnson's performance against the Broncos. I'm still not sure how the cornerback depth chart will play out, but I do hope Eric Mangini is less rigid than his secondary assignments than Vic Fangio was. San Francisco had a hard devotion to playing a guy in a spot and keeping him there rather than exploiting matchups. I think Johnson is a valuable weapon but at this stage in his development, he has to be used in very specific ways.