Almost nobody was surprised to see Iowa quarterback Jake Christensen and running back Shonn Greene atop the depth chart for Saturday’s opener against Maine.

What caught everyone’s eye was the absence of Nate Guillory.

Iowa coach Kirk Ferentz said Tuesday that Guillory, a junior college transfer expected to compete for playing time at running back, has left school and decided to transfer.

Guillory’s departure appears to have been based on playing time. With Greene as the No. 1 tailback and a host of young backs like Jewel Hampton and Jeff Brinson behind him, Guillory — who has two years of eligibility left — will likely seek out a program where he can play significant snaps right away.

“He was performing pretty well this camp, but it was stiff competition,” Ferentz said. “Probably the difference between him and a young player coming in is that his clock is running right now. I don’t want to speak for him, but I’m sure that was in his mind.”

Christensen can breath easy for now — after all, the starting job is his to lose — but it seems as though Ricky Stanzi gave him quite the battle in fall camp. In the end, Christensen’s status as the incumbent and a shoulder injury that limited Stanzi’s practice time swung the competition in his favor.

“The big difference right now is we know a lot more about Jake. He’s got experience, and very valuable experience, and he’s used that experience,” Ferentz said. “To me, we’re just a lot healthier at the position than we were a year ago, and that’s encouraging.”

That doesn’t mean Stanzi won’t play soon. The sophomore could see the field as early as Saturday, especially if the Hawkeyes can build a comfortable lead on the Championship Subdivision Black Bears.

“He’s throwing it stronger, he’s playing stronger, and just (doing) all the things you’d hope guys would do as they get a little bit older,” Ferentz said of Stanzi. “I think he’s ready to go in there and play, and we obviously feel that way about Jake too.”

Though Greene was expected to start all along, the path to a starting job in the Big Ten hasn’t been an easy one. After impressing in a limited role behind Albert Young in 2006, rushing for 205 yards on 6.4 yards per carry, Greene ran into academic trouble and spent last season at Kirkwood Community College.

The Iowa coaching staff always held out hope that Greene would get his grades in order, knowing there’d be a big hole in the backfield with Young and Damian Sims’ departure, and Ferentz said that Greene had a strong fall camp.

Iowa’s depth at running back is somewhat of a concern with Guillory’s departure, but Ferentz believes that the quality is there. Greene will be backed up by unheralded sophomore Paki O’Meara, out of Cedar Rapids.

“We expect our running backs to play well. I wasn’t so sure about it in January, or even April, although we knew the cavalry was coming to some degree with Shonn Greene. But it was a wildcard,” Ferentz said. “I think we’ve seen enough now to know that ... we have some guys that can help us and get the job done.”

Iowa will be missing some key players on Saturday. Tight end Tony Moeaki will be out with a foot injury. Wide receiver Trey Stross (hamstring) and offensive lineman Dan Doering (hand) will also miss the opener.

Iowa doesn’t know how long they’ll be without Stross, who has battled injuries throughout his career, but Ferentz said he’s hopeful Doering can begin practicing next week. Linebacker Jeff Tarpinian also has a hamstring injury. His status for Saturday’s game is still up in the air.