While re-watching the Eagles win over the Dolphins, it was hard to miss another poor showing by Nnamdi Asomugha. The $60 million cornerback isn’t shutting down many wide receivers these days.

On Sunday, Brandon Marshall got by Asomugha for an early touchdown, and later Brian Hartline (!) beat him for a 24-yard gain. Those two plays were the only ones where Asomugha’s receiver was targeted, but they were both successful.

It’s tough to tell exactly what’s wrong with Asomugha. While adjusting to Juan Castillo’s questionable schemes, he deserved the benefit of the doubt. But at this point it’s clear that something else is going on. He’s 30 years old and may have lost a step or two. But I rarely see Asomugha getting simply outrun or otherwise beaten physically. In fact, he stuck with Larry Fitzgerald as well as anyone during the Cardinals game.

Instead, I have a new theory, one that I arrived at after replaying the Marshall touchdown nearly a dozen times.

On that play, Asomugha actually had solid coverage. Nate Allen provided help over the top, and Asomugha kept pace with Marshall, mirroring his movements underneath as he broke outside in the end zone. Then the ball arrived, and… nothing.

It was a great pass by Matt Moore, but Asomugha was in fair position to break it up. Instead, he seemed surprised that the ball arrived. He gave a half-hearted flail and the ball sailed right into Marshall’s arms.

Asomugha’s cross-field running mate, Asante Samuel, gets beat more often than Eagles fans would like. He stares into the backfield and tries to jump pass routes. But regardless of Samuel’s deficiencies, one gets the sense that he expects the ball to come his way. Not only that, but he welcomes it, he wants it. Sometimes Samuel will make a mistake and allow a needless big play, but he’s confident that if the quarterback looks his way enough, he’ll make him pay.

Watching the Marshall touchdown again, and reflecting on Asomugha’s performance this season, I think Nnamdi’s biggest problem might be that he has the opposite attitude. He doesn’t expect passes to come his way, and he doesn’t really want them.

The most effective tool Asomugha had was his aura of invincibility. Other than the 2006 season, he never had more than one interception in any of his first eight years in the league — not because he was bad, but because quarterbacks never threw at him. In the last three seasons combined Asomugha only allowed one touchdown, while never being targeted more than 30 times a year.

This year, he’s on pace for 43 targets, a 45 percent bump from 2010. This wasn’t unexpected, considering Samuel is better than any of the corners Asomugha played with in Oakland. But Asomguha’s corresponding decline was surprising.

In short, I don’t think Asomugha has suddenly become a bad cornerback. Although his advancing age and new responsibilities don’t help matters, perhaps his biggest obstacle is mental. In the last few years with Oakland, Nnamdi surely realized that as long as he gave reasonably good coverage, his reputation will keep quarterbacks from testing him.

That’s simply no longer the case. And until Asomugha adjusts to the new reality, both expecting and welcoming the challenge of passes thrown his way, he’ll continue to be a coverage liability.

Photo from Getty.