He probably didn't like being 3rd or 4th receiver and realized he'd have to work harder.
Exactly. Here's what happened last year. He read and heard all the hype, and he believed it. "Freshman stud named Floyd coming in? No problem...I got this. Ain't anybody else on this roster that can't sniff my jock anyways."
And then Tate went Gangsta on everybody, and became an All-American seemingly overnight. And that Floyd kid turned out to be the REAL DEAL, and Kamara came in out of shape. He lost his hands, then lost his job, and never regained confidence. Plus he was playing catch up all year trying to get in optimum playing shape. I think he tasted a fine piece of humble pie, and he realized that not only were Floyd and Tate firmly entrenched as starters, but there were quite a few studs waiting in the wings.
Thus the new found work ethic. I hope he can catch the ball again, b/c I was very disappointed in him last year, and it's going to take a lot to regain the trust of Jimmy after all his drops/lack of toughness that cost him INT's last year. Let's hope he's the stud again that many (including himself) believed him to be...