With the addition of a top junior-college recruit, the return of a steady veteran and the promise of a few youngsters, Arizona’s defensive line this season should have all the talent and depth it needs to finally meet coaches’ expectations.

But to what extent will this potential show on the field? Defensive coordinator Mark Stoops and defensive line coach Mike Tuiasosopo both expect that answer to define the success of not only the line, but also the defense as a whole.

“”I think we have a lot of tough guys who want to work hard and make plays,”” Tuiasosopo said. “”You can’t go anywhere unless you have a defensive line. To me, maybe outside the quarterback, that’s the most important position.

“”Your team is dictated by how your D-line plays. We have an enormous responsibility, and I think we’ll be up to the task,”” he said.

The unit’s challenge will be twofold: shoring up a run defense that allowed the second-most yards in the Pacific 10 Conference last season and keeping the pass rush steady despite the loss of last year’s sack leader Copeland Bryan, who has used up his eligibility.

Stopping the run was a top focus all throughout fall camp, Stoops said, and Tuiasosopo added that fundamentals will be paramount in keeping opposing backs at bay.

“”We’ve challenged those guys to be tougher in the run game and just be better up front,”” Stoops said. “”I think the guys are working extremely hard. They want to be good.””

The responsibility of replacing Bryan, who had 7.5 sacks in 2005 for an Arizona squad with no returning player who had more than two, will fall to multiple players.

Tuiasosopo said he expects returning ends Marcus Smith, Johnathan Turner and Jason Parker, as well as junior-college transfer Louis Holmes, to all chip in their share of production.

“”They’ve had a lot of reps, they’ve seen the speed of the game and I expect different things from them,”” Tuiasosopo said. “”I’m excited.””

Much of the excitement surrounding the team this offseason centered on the arrival of Holmes. The nation’s No. 1 junior-college recruit, he joined the Wildcats for fall practice Aug. 4 after six months of uncertainty over his status.

Players and coaches alike have already marveled at the physical gifts of the 6-foot-6, 270-pound player, leaving his biggest obstacle to playing time being how quickly he grasps the playbook.

“”There are a lot of things fundamentally he has to get a little bit better at, understand that he can’t freelance,”” head coach Mike Stoops said. “”It’s too much in this defense. Everyone has controls and responsibilities, but the game comes easy to him.””

Mark Stoops said last week that Holmes should see time in the team’s season opener Sept. 2 against Brigham Young, and possibly even start opposite the fifth-year senior Smith, who has improved his strength and conditioning since suffering a season-ending ankle injury nearly a year ago.

Redshirt sophomore Johnathan Turner shined after being thrust into a starting role last season, earning third-team freshman All-America honors from The Sporting News.

That starting role could continue this season, though Mark Stoops said he would most likely split time with Holmes.

Both Turner and Holmes spent time with the first-team defense during fall camp, but Turner got the start at the team’s “”Meet the Team”” scrimmage Aug. 19.

“”As long as I get on the field, I’m OK,”” Turner said. “”If Louis comes in and he contributes to the team and he helps the defense, then that’s good for the team. I’m cool with that. It’s not an individual thing.””

Besides Holmes, the team’s strong recruiting over the past couple seasons has brought a new level of young talent to the line.

Players like sophomore Dave Bertrand and freshman Conan Amituanai, who will back up starting junior tackles Yaniv Barnett and Lionel Dotson, and sophomore Michael Shelton and freshmen Ricky Elmore, both defensive ends, give the Wildcats possibly their deepest unit under Mike Stoops and options for this year and beyond.

“”Teams won’t be able to focus on one key person like they were able to do last year with Copeland,”” Smith said. “”They’ll have to pay our whole D-line respect because if they focus on one (player), the other three are going to make plays.

“”It’ll even things out all along the line.””