If there's any team used to adjusting to the loss of a starting tailback, it's Iowa. And now it looks like the Hawkeyes might have to dig into their bag of tricks again.

Surprising star Mark Weisman is not listed on Iowa's depth chart that was released Monday for this weekend's Penn State game. Weisman suffered a right ankle injury that forced him out of Saturday's overtime win at Michigan State late in the game. He was wearing a walking boot on the foot after the game.

Iowa has not made any official comments on Weisman's availability for this week, and coach Kirk Ferentz will not address the media until Tuesday. But his absence from the depth chart is not promising, to say the least, especially with Penn State's stout defense coming to Iowa City in a battle of teams with unbeaten Big Ten records.

Weisman has rushed for 631 yards and eight touchdowns, with virtually all of that production coming in the past four games. Damon Bullock, who started the season at tailback before suffering a head injury, did not return as expected last week and isn't listed on the depth chart this week.

True freshman Greg Garmon, who missed some time with an arm injury, and Jordan Canzeri, who tore his ACL in spring practice, are listed as the top two running backs on the depth chart.

This looks like a challenging situation for a team that has been unable to generate many points at all out of the passing game. But if any team knows how to adjust from running back setbacks, it's Iowa.