David Cobb has a ready smile for anyone wondering if he's getting tired.

The Gophers senior leads the nation with 27 rushing attempts per game, but he's quick to note how little the team used him as a freshman and sophomore. He got 11 carries those two years combined.

"So I'm kind of fresh," Cobb says in a way that suggests he wishes he could take a handoff right now.

He's been so productive, racking up 1,013 yards through seven games, that the Gophers can't seem to help themselves. He's had 34, 32, 30 and 35 carries over the past four games — all victories — and Saturday the Gophers face an Illinois team that ranks last in the Big Ten in rushing defense.

"He's a back that seems to get stronger as the game goes on," coach Jerry Kill said Tuesday. "I keep saying every week, 'We need to take a few of those off of him.' It's hard to do, when he gets into a rhythm. But I think we need to be careful."

The Gophers record for rushing attempts in a season is held by Thomas Hamner, who had 308 over 12 games in 1999. At Cobb's current pace, he would finish the 12-game regular season with 324 carries, and 351 after a bowl game.

"He's a gamer," offensive coordinator Matt Limegrover said. "I think he would be disappointed if he wasn't there at a key point in time. But you have to make sure — the last couple of years we've run out of gas, as an offense. So we're also really looking at ways we can make sure that we stay strong right up until the end of November."

The Gophers believe they have good tailback depth behind Cobb, even if they've been reluctant to use it. Fellow senior Donnell Kirkwood led the team with 926 rushing yards two years ago, but he's averaging 2.3 yards per carry, compared with 5.4 for Cobb.

Still, with the score tied against Purdue in the second quarter last week, the Gophers kept Cobb on the bench while Kirkwood finished off a drive with three rushes, including a punishing, 3-yard touchdown.

Speedy freshman Berkley Edwards looked as if he'd be more of a factor when he rushed for two touchdowns, including a 42-yarder, in the season opener against Eastern Illinois. But he suffered a shoulder injury and has only one rushing attempt over the past two games.

Junior Rodrick Williams appeared to be the No. 2 tailback option for a while, but he's gone without a carry the past two games.

"It's hard when you have a kid that's going like David is," Limegrover said. "He's so strong. You look at him during the ballgames, he never looks exhausted. He never looks like he needs to come out.

"It isn't anything that Rodrick necessarily has done right or wrong, per se. It's just a matter of having a guy that's really feeling it right now."

Cobb, who needs 451 more yards to break Laurence Maroney's single-season Gophers record, ranks fourth in the nation in rushing, at 144.7 yards per game. The three rushers ahead of him all come from the Big Ten — Wisconsin's Melvin Gordon (174.3), Indiana's Tevin Coleman (170.3) and Nebraska's Ameer Abdullah (146.3).

None of those other backs averages more than 23 carries per game, but last year, the nation's two leading rushers were Boston College's Andre Williams (27.3 carries per game) and Arizona's Ka'Deem Carey (29.1). Two years ago, Michigan State's Le'Veon Bell led the nation with 29.4 rushing attempts per game.

So there is a precedent for this kind of workload, and Cobb insists he welcomes it. After rushing for 194 yards Saturday against Purdue, he was asked if he ever gets tired.

"Never, when you're winning," he said, with another big smile.