UNIVERSITY PARK — Penn State’s running game has plodded along for four games, jettisoning the injured for the healthy, waiting for a moment to feel rejuvenated.   

That moment arrived Monday.

Slick sophomore Bill Belton returned to the serious portions of practice, and in the words of coach Bill O’Brien, “looked decent.”

O’Brien followed the assessment with an encouraging statement. “We would anticipate him being ready to go for the game,” he said.

The game isn’t a normal one. Penn State (2-2) begins Big Ten play Saturday at Illinois (2-2).

If the injury report and interview clips are to be believed, the Nittany Lions could be bringing a loaded backfield to Champaign, Ill.

Belton, who became the top tailback when Silas Redd transferred to Southern California, has rested his sprained left ankle for three weeks. He’s listed as probable.

Senior Derek Day, who became the top tailback when Belton went down, has rested a separated shoulder for two weeks. He’s listed as probable.

“I’m feeling really good,” Day said. “It’s excellent to be on the field getting reps in practice and really exciting to have the opportunity to hopefully get back on the field on Saturday and contribute.”

Belton and Day aren’t the only backs preparing for work against Illinois.

Senior Michael Zordich, a fullback turned tailback because of Belton and Day’s injuries, is recovering from a knee injury he suffered during his career-high 15-carry, 75-yard effort last week against Temple. Zordich didn’t practice Monday, but he returned to the field Tuesday. Zordich predicted he would play Saturday.

“I took a hit,” he said. “That’s all really. I got a little banged up and will be all right for this Saturday and the rest of the season.”

O’Brien seems convinced Zordich will be available. Zordich, after all, is the son of former Penn State and NFL player, Michael Zordich, and hails from blue-collar Youngstown, Ohio.

“He’s a tough kid,” O’Brien said. “I’m sure he’s on the phone with his dad and his dad is telling him to get his butt back in there.”

Junior Curtis Dukes didn’t occupy a line on the injury report. But he didn’t run the ball last week because of a thigh injury. O’Brien dropped Dukes into a category with Day and Zordich on Tuesday.

“They all look fairly healthy right now,” O’Brien said.

The only Penn State running back who hasn’t been slowed by a visible ailment this fall is sophomore Zach Zwinak, the holder of Penn State’s top 2012 rushing performance. The 6-foot-1, 232-pound sophomore gained 94 powerful yards on 18 carries last week.

A healthy backfield could help a meager rushing offense. The Nittany Lions average 124 rushing yards per game, which ranks last in the Big Ten. They are averaging 3.7 yards per attempt and own a conference-low two rushing touchdowns.

It’s unlikely all five running backs will receive major offensive roles this week. O’Brien said he plans on trimming his options to two or three players based on practice performance. Practice starts are alternated, with backs rotating before each team period.

“We’ve got a good situation there with some tough kids that can run the ball, pass protect and catch the football,” O’Brien said. “So we’re going to continue to compete at that position.”

Day likes the Nittany Lions’ mix. Zordich, Dukes and Zwinak are considered bruisers. Belton is an outside running and receiving threat. Day views himself as a hybrid.

“I think it gives us the opportunity to go out there and do different things and create different game plans for each week,” he said.

“I think having a lot of versatility in our running back room is really beneficial for us.”

Notes: O’Brien said senior defensive end Pete Massaro  “probably will not play” against Illinois. Massaro hasn’t played since injuring his shoulder at Virginia. O’Brien listed defensive end Sean Stanley, who missed the game Temple with a back injury, as probable. Stanley is listed as a starter on Penn State’s depth chart.

Guy Cipriano can be reached at 231-4643. Follow him on Twitter @cdtguy