SOUTH BEND, Ind. -- New Notre Dame coach Brian Kelly likes the potential he sees in his team's offensive line, even if the Fighting Irish seem to tweak the starting unit every day of spring practice.
Kelly likes Notre Dame's athleticism, the variety at wide receiver and his team's depth at running back. He even sees encouraging signs from the defense, which ranked among the country's most porous units in 2009, former coach Charlie Weis' final season.
After two weeks of spring practice, Kelly knows what will determine whether the Fighting Irish are successful in his first season in South Bend: the play of quarterback Dayne Crist.
Kelly and his coaching staff have less than five months to get Crist ready to play before the Fighting Irish open the 2010 season against Purdue at Notre Dame Stadium on Sept. 4.
"When you cut through it, we're going to be tied to his ability to run our offense," Kelly said last week. "He's extremely capable of being what everyone wants the Notre Dame quarterback to be, but he's got no résumé. He hasn't played."
Crist, a junior with three years of college eligibility remaining, attempted only 20 passes in four games as Jimmy Clausen's backup last season. Worse, Crist tore the anterior cruciate ligament in his right knee in the second half of a 40-14 blowout of Washington State in San Antonio, Texas on Oct. 31.
Less than five months after undergoing surgery to repair the damage in his knee, Crist is being asked to step into Clausen's enormous shoes -- and learn the intricacies of Kelly's spread offense -- during spring practice.
"We're cheating nature a little bit, but it was so important for me to get him out there because he just doesn't have much experience," Kelly said. "Our defensive coaches are responsible for protecting him. If you can't protect Dayne Crist, you're not going to be coaching here."
Keeping Crist healthy might be Notre Dame's No. 1 priority during spring practice. He's the only scholarship quarterback on its roster who won't be entering his first season with the team in 2010. Walk-on Nate Montana, son of former Irish and NFL star Joe Montana, is currently the No. 2 quarterback. Freshman Tommy Rees, who enrolled in classes in January, also is participating in spring practice. Two more freshmen -- Andrew Hendrix and Luka Massa -- are expected to join the team this summer.
"I'm trying to embrace every challenge," Crist said. "I think we've got a great offense in place. I think we have a great team. I think it all depends on how we come together as a team."
Crist, 20, was one of the country's most heavily recruited quarterbacks as a senior at Notre Dame High School in Sherman Oaks, Calif. In 2007, his senior year, he passed for 2,178 yards with 16 touchdowns and one interception, while running for 454 yards with four touchdowns. A 6-foot-4, 235-pound native of Canoga Park, Calif., Crist is expected to be more mobile than Clausen when he recovers fully from his knee injury.
Clausen, who left Notre Dame after his junior season to enter this month's NFL draft, was one of the most successful passers in the school's history. But the Fighting Irish went only 16-21 the last three seasons, the most losses in a three-year span in Notre Dame history.
For now, Crist is trying to absorb as much of Kelly's spread offense as possible. Last season, Kelly's offense at Cincinnati ranked in the top 10 nationally in scoring (38.6 points per game), passing (308.7 yards per game) and pass efficiency (161.2 rating). Bearcats quarterback Tony Pike ranked 12th nationally in passing efficiency (149.8) and was a Heisman Trophy candidate before injuring his left wrist in the sixth game last season.
"I think it's definitely faster than anything I've ever experienced," Crist said. "Once we get a greater knowledge of his offense, I think we'll be operating a lot faster."
Kelly believes the Fighting Irish have plenty of pieces around Crist to help him be successful. Senior Armando Allen Jr. and Robert Hughes combined to run for more than 1,000 yards last season. Junior Michael Floyd caught 44 passes for 795 yards with nine touchdowns, and junior Kyle Rudolph has the potential to become one of the best tight ends in the country.
The Irish must replace three starters on the offensive line, but Kelly called the returning unit his team's "most fundamentally sound group" on offense.
This coming season, it will be Crist's job to make the offense come together.
"He's getting the gist of the whole offense and learning to be a quarterback," Floyd said. "You have to be able to handle everything quicker than everyone else when you're the quarterback. It's really starting to come together for him."
The Irish can only hope they have more luck with Crist than with their last two first-year starting quarterbacks. Notre Dame went 5-7 with Brady Quinn under center in 2003 and 3-9 behind Clausen in 2007.
"There are enough pieces on offense," Kelly said. "At the end of the day, it's going to be up to our ability as coaches to get Dayne Crist to play consistently from week to week."
Mark Schlabach covers college football and men's college basketball for ESPN.com. You can contact him at email@example.com.