INDIANAPOLIS -- Indianapolis Colts running back Trent Richardson stood at his locker on Thursday afternoon and answered every question thrown his way about being benched and how the past week has been for him.

He called the experience humbling because it was the first time since his sophomore season at the University of Alabama that he wasn’t his team’s starting running back. Richardson said Donald Brown deserves to be the starter and they'll continue to push each other.

I caught up with ESPN.com NFL scout Matt Williamson on Thursday to talk about Richardson’s struggles this season:

Williamson on the trade:

“First of all, when the trade happened I thought the Colts made a great move. I liked him out of Alabama and what he did as a rookie with the Cleveland Browns. Every defense was keying on him and he was able to be productive, especially as a receiver. I thought he was going to be -- not Adrian Peterson -- but I thought he would be a Pro Bowl back and was worth what I expected to be a late first-round pick. Of course it hasn’t worked out. I think there have been a lot of reasons. Some of it is bad luck, some of it is coaching. But a lot of it is on him.”

Williamson on why Richardson has struggled:

“Just looking at him, I think he’s been tentative since he’s been here. I feel like he’s uncomfortable knowing when to hit the holes and what their scheme is. He’s lost mentally. It doesn’t mean he’s not smart. I think he’s not tuned in to exactly what they’re doing. It’s not natural for him, not knowing exactly where to go, thinking too much. That shouldn’t be a shock, though. He joined a new system in midseason. Running back is one of the hardest positions to learn. He hasn’t been through minicamp or training camp. He also deserves some blame, too. He isn’t running with that aggression. He doesn’t look like he has that burst that he had at Alabama or last year. He is tentative when there are holes there. He doesn’t attack them like he should.”

Williamson on other reasons behind Richardson’s problems: