Although Notre Dame must replace Darius Walker and his 1,267 rushing yards next fall, Irish coach Charlie Weis said Monday that he is “very encouraged” by the progress of his running backs this spring.

Four tailbacks – senior captain Travis Thomas, rising sophomore James Aldridge, rising senior Junior Jabbie and early entry freshman Armando Allen – are in contention to replace Walker, who accounted for 77 percent of Notre Dame’s carries by running backs last season.

“The competition is every day and in everything we do,” Aldridge said.

Thomas is the most experienced player of the four and, as team captain, is the leader of the group. But he played outside linebacker last year, making 35 tackles in 11 games. He saw spot duty at running back, gaining 78 yards on 13 carries and scoring two touchdowns.

In 2005, Thomas was the second leading rusher for the Irish. He ran for 248 yards on 63 carries with five touchdowns in his sophomore season.

Back full time at running back, Thomas started the spring as the top backfield option for Notre Dame, but Weis said Aldridge is pushing to at least split carries next fall.

“He’s definitely challenging,” Weis said of Aldridge.

Aldridge was the team’s second-leading rusher last season, gaining 142 yards on 37 carries, mainly in mop-up duty. He played in seven games despite suffering a knee injury before the season started.

But now, Aldridge says he’s healthy and ready to show an explosiveness that he lacked last season.

“I’m getting used to bending my legs like I want to and exploding up,” he said. “I’m just trying to get better.”

Aldridge said the simple act of removing the knee brace has improved his explosiveness.

“I’ll be a lot quicker [than last year],” he said. “My lateral movement will be back to what it used to be.”

Weis said he has seen dramatic improvement as well.

“He’s night and day from where he was last year,” Weis said. “Last year, he was never really healthy. I didn’t see his second gear much last year.”

Joining power backs Thomas and Aldridge are the quicker – but much less experienced – Allen and Jabbie.

Allen, who enrolled at Notre Dame in January, has impressed the Irish special teams staff with his quickness on kick returns. Weis said that even though wide receivers David Grimes and George West will be back next fall, he prefers to use a younger player as return men in order to avoid tiring the starters.

“When it’s otherwise even, you use a back up,” he said.

But the coaching staff has not ruled out Allen appearing in the offensive backfield as well, Weis said.

“He hasn’t looked like a freshman,” the coach said.

Weis said Jabbie, a former cornerback without a career carry for Notre Dame, is working hard to see the field next fall.

“I’ve been very encouraged by Junior Jabbie,” he said. “I’m not just giving the party line. I’ve been very encouraged by what we’ve seen.”

Rising sophomore Munir Prince, a former running back that rushed for 21 yards on 14 carries last year, began the spring at running back but has since moved to cornerback.

At fullback, rising junior Asaph Schwapp returns after missing most of last season with an injury. Weis said Schwapp, a 6-foot, 255-pound bruiser, is completely healthy and has regained his toughness as a lead blocker. But he has a way to go as a runner.

“He’s not hobbling around any more,” Weis said. “But he has room for improvement.”

Rising sophomore Luke Schmidt will also compete for playing time at fullback, Weis said.