This is where the wannabes begin separating themselves from the guys who aren't quite ready.

This year, more than any in recent memory, the Tennessee football team has to fill a lot of holes on the offensive line, defensive line and at linebacker.

Today is the first major step.

The Vols have a full scrimmage scheduled for this afternoon at Neyland Stadium.

UT head coach Phillip Fulmer is using it to challenge those Vols still in search of some playing time.

"There are a lot of guys who could be significant contributors on this team if they would just take that next mental step," Fulmer said on Friday.

"With some it might be maturity, their understanding of football at this level. With some it might be a position change and X's and O's. We have to take those steps in the next two or three scrimmages."

Fulmer talked specifically about the defensive line.

Senior defensive tackle Justin Harrell has his spot. Turk McBride could play at end or tackle, but he'll definitely be somewhere. Other than that, it's a question mark.

"It (defensive tackle) is one of the positions we need people to come on and take that next step to show us they can consistently play at this level," Fulmer said. "We know J.T. (Mapu) can, but he's not necessarily 100 percent in football shape yet (after a two-year layoff on a Mormon mission).

"Dan Williams and Demonte Bolden really haven't showed yet they can play consistently at this level. They've shown flashes, but nothing consistent."

The Vols are looking for depth as much as anything else.

"We'd like to play five or six defensive ends and five or six defensive tackles, but we can't do that right now," Fulmer said.

Sophomore defensive end Robert Ayers isn't cutting loose just yet like Fulmer would like to see.

"He broke his hand and it looks to me he's feeling sorry for himself a little bit," Fulmer said. "It's something he needs to forget about and go on and play."

At linebacker, Fulmer singled out freshman Dorian Davis and sophomore Ellix Wilson for pushing the starters.

"I'm really tickled with what Dorian Davis is doing right now," he said. "He's one of those guys, if he closes ground a little bit, could get himself into the rotation.

"Dorian has a lot to learn, but he has shown the athletic ability to be a player here."

Another area of concern is at center.

Fulmer said junior Michael Frogg, freshman Josh McNeil and sophomore Anthony Parker each will get looks with the first team today.

"Anthony will be starting at guard (ahead of Ramon Foster), but we're going to get our best five out there," Fulmer said. "The two centers (Frogg and McNeil) have been OK, but they've been a little on the slow side to respond to the level we want them to be at."

Steven Jones is third in the offensive tackle rotation, and Fulmer said the junior from Brentwood is pushing for a starting spot.

"It's not out of the question he's a starter before this camp is over," Fulmer said. "He has done very well. He's pushing Eric (Young)."

Jacques McClendon, another freshman from Chattanooga Baylor, is already running at second-team guard.

"He's very physically gifted, but fundamentally and technique wise had no idea," Fulmer said. "He's another guy if he goes on and keeps progressing, he's as physically gifted as anyone we have up there."

Limited today: Freshman running back Montario Hardesty won't be at full speed today after a setback with his knee earlier this week.

"His knee (the same one that underwent ACL surgery last year) is swollen up some and we will be very careful with him," Fulmer said. "We need to get this thing under control and see what he can do."

Fulmer said junior defensive end Xavier Mitchell (shoulder) could be released for contact as early as Monday.

Sophomore defensive end Walter Fisher (shoulder) could be cleared "in the next couple of weeks."

Senior fullback Cory Anderson sat out practice Friday with a sprained knee, but Fulmer said he expects Anderson back today.

Also back at practice on a limited basis Friday was freshman receiver Slick Shelley. He had a minor abdominal operation last week.

Stephens has the arm: Freshman quarterback Nick Stephens has impressed Fulmer with his strong arm.

"He's as good as I've seen with his arm strength," Fulmer said. "He has to learn to study the game more and prepare himself.

"If you sit around and wait your turn, people will come in and pass you up."

Williams/Raines non-update: Fulmer said there was nothing new to announce on the status of freshmen Gerald Williams and Stephaun Raines.

Both are still awaiting positive news from the NCAA Clearinghouse on academic issues.

The longer they have to wait, the less opportunity they'll have to contribute to the Vols early this season.

"It's getting close to that now," Fulmer said. "You talk about conditioning and we're inserting a lot right now.

"It's a little different with Gerald at defensive end, because he has been in the system a little bit."

Williams spent two weeks in Tennessee's camp last year, but didn't receive NCAA clearance. He's still waiting.

Casey update: For now, Casey Clausen is out of the football business and into the insurance business in California.

The former UT quarterback worked the past two season as a graduate assistant for the Mississippi State Bulldogs.

Tee update: Tee Martin, quarterback during the Vols' run to a 1998 national championship, is quarterbacks coach at Morehouse College in Atlanta.

Martin previously had stints in the NFL with Pittsburgh and Oakland. He played for the Winnipeg Blue Bombers of the CFL in 2005.

Mark Burgess covers University of Tennessee football. He may be reached at 865-342-6277.