In August, Bill O'Brien said that he would like running back Bill Belton to get 20 to 25 carries a game.
Five games into the season, it's clear O'Brien's initial plans have been amended.
"I think that's changed a little bit," O'Brien said Tuesday. "At the beginning, I said that. But we have got some good guys back there, and they all it's really a competitive in practice."
They've stepped up because of opportunity.
Belton -- a high school quarterback turned wide receiver turned running back -- entered the season with the dubious distinction of being Silas Redd's replacement.
Belton was steady, and at at times impressive, in Penn State's season-opening loss to Ohio. That is, until the third quarter when Belton injured his ankle.
He missed the next three games before returning for last week's Big Ten opener against Illinois. The Nittany Lions went 2-1 over that stretch, and replaced Belton by committee. It was a new starter every week, and a new breakout star every week. Former walk-on Derek Day was steady against Virginia, 6-foot-1, 245-pound Curtis Dukes plowed through Navy's defense then senior Mike Zordich demonstrated his versatility and explosiveness against Temple.
In the Illinois game, when Belton finally returned, it perhaps should have been to nobody's surprise that a new back emerged as a threat.
Zwinak ran for two touchdowns in an 100-yard effort, he first for a Nittany Lion since Silas Redd went for 137 against the Fighting Illini last season.
Belton, meanwhile, ran for 65 yards on 16 carries.
"We ran the ball 52 times in the Illinois game, so nobody is going to really carry it 52 times for us," O'Brien said. "Nobody is going to carry it 30 times for us. It's more about that 10 to 15 carry range, probably right now. Things change as the season goes on."
Belton said that he woke up on Sunday morning and his ankle felt "great." He said he still needs to work on carrying the ball closer to his body, but that's something running backs coach Charles London and O'Brien have been stressing all season.
In the three weeks he was gone, Belton was with the training staff "pretty much all the time." He said he replayed the Ohio game over and over in his head, thinking of things he could improve on.
"I wanted to get back," Belton said. "So I did possibly anything to get me back. That's kind of the way I look at how my three weeks were."
As the Nittany Lions prepare for Northwestern, it's hard to predict what role Belton will play. He and Zwinak complement each other -- Belton is faster and shiftier while Zwinak pounds through defenders -- but will the workload be 50-50?
If Belton is really at full strength, could it be that his peers are closing in on the gap?
"[Belton is] a guy that can really have a big effect on the game and he's got great feet and he's got good speed and he can catch the ball in the backfield," O'Brien said. "So as long as he stays healthy, he'll always be a part of our game plan."
Indeed Belton will always be a part of the game plan. But week by week, O'Brien seems to be rearranging his math.