The University of Virginia football team opened preseason camp Friday without star linebacker Ahmad Brooks on the field, and Cavaliers Coach Al Groh isn't sure when his all-American and potential NFL first-round draft choice will be ready to practice.

Brooks, from Hylton High School in Woodbridge, is still recovering from December surgery to correct a degenerative condition in his right knee. Doctors corrected the junior's injury through surgery that is designed to stimulate bone growth in his knee. But because Brooks was unable to participate in spring practice or during much of the team's summer offseason conditioning program, Groh said the linebacker isn't ready to practice.

"Right now, he's out so he's not in the plans. When he's back, he's back," Groh said. "He is medically cleared. But he is still in his rehab, and the building-himself-back-up stage. He hasn't been able to train hard enough to this point to participate in what we're doing."

Brooks, wearing blue shorts and an orange T-shirt, did some light jogging on the sideline while his teammates practiced in shorts and helmets during Friday's practice.

"We want to make sure it's not a circumstance where his knee is just fine, but then he misses a significant period of time because he's got a pulled hamstring or pulled groin muscle or whatever because those muscles weren't given the opportunity to be properly conditioned," Groh said.

The Cavaliers already face the daunting task of replacing Darryl Blackstock and Dennis Haley, who started every game at outside linebacker last season, as well as backup inside linebacker Rich Bedesem, who started the 2004 opener against Temple in Brooks's place. Brooks, the youngest of three finalists last year for the Butkus Award as college football's best linebacker, led Virginia with 90 tackles and 11 quarterback pressures.

Brooks, the son of former Washington Redskins defensive tackle Perry Brooks and the 2001 All-Met Defensive Player of the Year, could have left Virginia after his sophomore season because he was three years removed from high school. Most NFL scouts consider Brooks to be among the top 10 underclassmen for next April's NFL draft. Groh said he had big plans for Brooks during the offseason, but the program was shelved when Brooks underwent surgery.

"It's one of the circumstances of life," Groh said. "These things happen, so you go on. Obviously, this is a player of substantial talent and very special talent. After two years of playing, we had a real plan in place. We said: 'Here's what we're going to work on to magnify this special talent to its highest level. So the next year, it's going to be different than the first two, not just on talent alone but through mastery of all these particular things.' "

Groh couldn't say how long it would take Brooks to get into playing shape. The Cavaliers, ranked No. 23 in the USA Today coaches' preseason top 25 poll, open the season Sept. 3 against Western Michigan at Scott Stadium.

"There really hasn't been much physical work since late December," Groh said of Brooks. "The player that we had back then was pretty good. It will be interesting to see when Ahmad does come back to play, is this the same player that was playing in December? A very good player, but the same player. Or is this going to be a player that's had the opportunity to raise his game?"

With Brooks sidelined for now, senior Bryan White probably will play next to junior Kai Parham at inside linebacker. White, a senior from Knoxville, Tenn., played in only one game last season before undergoing back surgery. Sophomores Jermaine Dias and Marvin Richardson and redshirt freshman Clint Sintim are the leading candidates to start at the two outside linebacker spots.

The Cavaliers also signed five linebackers in their incoming freshman class, including Olu Hall of Robinson High, who played last year at Hargrave Military Academy.

The Cavaliers don't know when all-American linebacker Ahmad Brooks will be able to practice.