With guys like Ekpre Olumu, and any corner 5'10 or shorter, when I watch, the biggest thing I'm looking for is do they have the ability to prevent completions on plays where the receiver is in between the cornerback and the quarterback. For example, covering a hitch route, if you are unable to jump the route, how do you plan on breaking up the pass? If you are a 5'10 corner against a 6'3 receiver, your arms are shorter than that of the receiver and if you can jump the route, no matter how close you are to the ball, the receiver is closer than you. Being behind a receiver with longer arms than you is a tough matchup, no matter how close you are to him. You can't straight up deflect the pass, since it will touch his hands first. So how do you prevent the catch, in a scenario inevitable for all corners? It's not easy. The first thing that most successful 5'10 corners do is hit the receiver within about .01 seconds of him touching the ball. The timing must be nothing short of impeccable, and it's not something you can teach. You then wrap your arms around receiver, try to rip his arms apart, but also tackle him, whether or not you think you broke up the pass, just so that in the worst case scenario it's only a 6 yard gain.
Jason Verrett is perfect about this. So is Ronde Barber, Antoine Winfield, and Brandon Flowers. Ekpre-Olumu hasn't shown me he can do this. If he yields inside position, the only way he can stop the route is by jumping it. And that's why he is overrated