Asked about Marcus Cooper’s skill-set, Kansas City Chiefs head coach Andy Reid spoke with admiration.”He’s big, he’s fast, and he’s got good cover and good hips,” Reid said. “It looks like he’s very instinctive with things. He’s young at the position; he’s young in the league and he played wide receiver at Rutgers, before. It’s just a matter of reps. Sure, he’s competitive. I appreciate seeing that.”

Cooper changed positions only three years ago. He was a wide receiver at Rutgers, as Reid said, but then a hand injury forced him to switch to cornerback. So it’s understandable that he’ll struggle at times this season, his first of extensive action.

The Chiefs have given him plenty of snaps (as much as 80 in a game) and have frequently left him on the perimeter in press-man coverage. Although he’s done surprisingly well thus far, it’s no easy task on a weekly basis, especially for a guy who’s still learning the technical side of the game. One misstep, and it’s over.

He found that out the hard way in Week 9 against the Bills. He was thrown at nine times and gave up four completions for 71 yards and a touchdown, according to Pro Football Focus. But even on the plays he didn’t see the ball come his way, he struggled. He was beaten at the line multiple times, showing that he still has plenty of room to grow into a top-tier cornerback, which he may very well become once he puts it all together.

The first of the plays came with less than two minutes left in the first quarter. He was lined up on the perimeter (bottom of screen in white sleeves) opposite rookie Marquise Goodwin, a third-round speedster out of Texas, in press-man coverage. In this type of coverage, it’s important to jam the receiver by getting the hands up, sliding the feet forward, and rocking one of the shoulders. If the jam is missed, catching up to the receiver will be difficult and nearly impossible in this case, as Goodwin has a background in Olympic track and field.

At the snap, Goodwin jabbed his right foot out as if he was releasing outside and then shifted his shoulders inside. It was over then. Cooper committed a false step, mistakenly stamping his left foot into the ground and then attempting to slow down Goodwin with a long right-handed punch that he ultimately missed. Goodwin released freely inside and got on top of the numbers of the ‘Go’ route, blazing by Cooper and safety help for a 59-yard score.

A quarter later, Cooper was beaten at the line once more. There were four and a half minutes left in the second quarter when the Bills set up in shotgun on 3rd-and-3. Cooper lined up at the far side of the field (top of screen) rolled up to the line in press-man coverage against T.J. Graham, who was outside the numbers.

When the play began, Graham released outside like Goodwin did on the previously described play and then smoothly rolled his hips back to the inside. For Cooper, it was over then. As soon as Graham stepped outside, Cooper opened his hips up and found himself facing the sideline, a cardinal sin at the line in press-man coverage. That gave Graham an uninterrupted release inside for a quick slant.

Nearly two minutes later, Cooper was beaten again by a similar release. Again in press-man coverage outside the numbers (top of screen), he had his hands full with rookie receiver Robert Woods. Although inexperienced, Woods has lateral quicks and a sharp mind, which is why it was unsurprising when he took one step forward, jabbed his right foot out to make Cooper open his hips up, and slanted inside.

Winning at the line of scrimmage is imperative for Cooper in the Chiefs’ defense because it’s heavily based on press-man coverage. Mistakes can’t be made in this type of defense, especially at the line where Cooper must jam the receiver and disrupt the route.

Like any young cornerback, he has a lot of room to grow, particularly in keeping patient and his hips squared until the receiver commits to the stem of his route. It’s something he’ll have to learn by watching film, which he does plenty.

Despite his mistakes against the Bills, Cooper can be one of the league’s best cornerbacks as Chiefs general manager John Dorsey explained in October. “He can be as good as he wants to be. He has a high ceiling. He can turn and track the vertical throws and catch the ball. He’s got ideal length .. that’s the ideal press corner.”

Now all he needs to do is improve on the technical side of the game.