Tennessee football coach Phillip Fulmer laid out a challenge to his team after Tuesday’s practice, their first since returning from spring break.

"We’ve got a big separation between the guys who have played in games and know what they’re doing and those who don’t," Fulmer said. "There’s too much of a drop-off between the next level of guys. They've got to close that ground so we can count on them a bit."

Fulmer has said throughout spring practice that he is happy with the first team. He has said this spring, like most, is for young players to improve. Evidently, they haven’t done so.

"We’ve got a bunch of young guys who are very talented but haven’t played a lick," Fulmer said. "A lot of them don’t understand what it takes to play in the Southeastern Conference. They’re trying, I believe, but the problem is they’ve never pushed themselves.

"It’s going to be 95 or 100 degrees when we go to Florida. Nobody’s going to feel sorry for you when we go to LSU. Who’s going to have it in the fourth quarter and have the toughness to be a Tennessee football player? Those are the things you’re trying to answer here in spring practice."

Fulmer said UT’s inability to find a healthy, competent center has affected the entire offense’s ability to hold an efficient practice. Fulmer said Cody Douglas was the first-team center on Tuesday. The senior is still limited with a sore knee and has played guard for most of his UT career.

Junior David Ligon is still learning the position. Freshman Cameron Mayo is sidelined with a knee injury that Fulmer said was disconcerting. Freshman Anthony Parker has also played some center.

"We haven’t run the ball worth a flip yet," Fulmer said.

The one positive ? defense.

"Our defense is setting the tempo pretty darn well," Fulmer said. "I like that. The defense should be ahead. If you can play defense and kick it, then you can win. I hope we can score some points. I think we can when we get it all put together."

Stout Simon: Senior linebacker Kevin Simon was in full pads and participated in some hitting drills barely more than seven months after he suffered an anterior cruciate ligament tear in his left knee.

"It’s amazing what medicine can do these days," fellow linebacker Jerod Mayo said. "He’s out here running. He did a little hitting today. Soon, he’ll be back in the flow of things."

Safety Stew: Fulmer said defensive back Antwan Stewart is not completely cleared from the ACL injury he suffered in last year’s spring practice. Fulmer said, once that happens, coaches will play Stewart at safety and move either Jonathan Hefney or Roshaun Fellows back to cornerback. The two sophomores have played safety this spring after starting several games last year at cornerback.

Back from track: Junior defensive back Jonathan Wade practiced on Tuesday for the first time this spring. He was excused to run track.

Beefed Up: Freshman Ja’Kouri Williams said he has gained 15 pounds since he enrolled last summer.

"The weight room here has helped a lot," said the trim 190-pound tailback. "I have been able to run through a lot more arm tackles than I was doing at first. I have been able to take licks and bounce off them a little bit better then when I was 175."

Limited: Several Vols were short of full pads in practice. Wide receivers C.J. Fayton and Chris Hannon only participated in formation and short passing drills. Nearly a dozen players were wearing green non-contact jerseys.

Fulmer said junior wide receiver Jayson Swain is still limited with a hamstring injury.

Out: Senior defensive back Jason Allen (shoulder) and junior linebacker Daniel Brooks (hand) were held out of practice.

Oops: Senior defensive tackle Jesse Mahelona switched jerseys in the middle of UT’s stretching period. He began with LaRon Harris’ No. 91 instead of his usual No. 55.