What's going on with Penn State running back Bill Belton?

Bill Belton has been hampered by an ankle injury since the season-opener against Ohio, but on Saturday the running back was healthy.

Belton, a sophomore, is undboutedly the Nittany Lions' fastest, shiftiest and perhaps most naturally talented back. Then why was he benched for most of Saturday's game against Purdue?

On Tuesday, coach Bill O'Brien offered a few answers. It has to do with practice. Yes, practice. And no, not in the way Allen Iverson was talking about in his iconic speech.

"From day one that I arrived here, we talked to our guys about the importance of practice," O'Brien said. "Everything you get is earned on the practice field. There's no message being sent. That's what we do. There's a reason why you practice. You practice to compete. Life is about competition, and we try to be as fair as we can."

In that case, it appears that Zach Zwinak had a better week of practice than Belton.

Zwinak started and ran for a career-high 134 yards on 21 carries. Penn State's rushing attack totaled 185 yards. Belton played for one snap in the second quarter -- and that's it.

O'Brien has insisted since the start of the season that each week opens up a new competition. That's what Zwinak credits to his rapid development this season.

"It makes us better as a running back corps," Zwinak said. "We push each other."

Who will push harder in practice this week? Stay tuned Saturday.

On the depth chart for Nebraska, the first-team running back is listed as Belton OR Zwinak.

-Emily Kaplan