Dorrell trying to shore up backfield

UCLA Coach Karl Dorrell’s concerns about the depth in the Bruins’ backfield reached the point where he was ready to tinker Tuesday.

Safety Christian Ramirez was shifted to tailback and linebacker Fred Holmes to fullback for practice, though Dorrell said neither switch was permanent.

“We put them over there this morning just to see what they can do,” Dorrell said.

Still, there is no doubt Dorrell is seeking Rogaine-like solutions to his rapidly thinning backfield. Chris Markey and Kahlil Bell are the only healthy tailbacks on scholarship. Fullback is an even dicier situation. Dylan Rush, a converted defensive end, is the only healthy fullback available -- and he has struggled during training camp.

Fullback Michael Pitre was in full pads Tuesday for the first time since reinjuring his left knee 11 days ago. Dorrell was hopeful that Pitre, who performed some individual drills, would be ready for full workouts by the end of the week. Fullback Trevor Theriot (strained hamstring) suited up but was held out of drills.

Even if both return, the need for depth in the backfield is evident.

Holmes, a senior, has never played fullback before but “was willing to at least show what he can do,” Dorrell said. Ramirez is the more intriguing candidate, having rushed for 2,796 yards at Imperial High in El Centro, Calif.

Ramirez churned out a couple of respectable runs Tuesday, and Holmes familiarized himself with blocking responsibilities.

“[Ramirez] was our sixth safety, so he doesn’t get a lot of reps,” Dorrell said. “He has running back in his background. We wanted to give him a chance. He didn’t look like he’d lost too much from where he was as a high school player.”

The transition would be easier for Ramirez.

“If they’ve had experience before, it doesn’t take that long,” said Dino Babers, who coaches the running backs. “Someone who has never done it before, like Holmes, sometimes it takes a while. We saw some encouraging things, but we’ll have to check the tape. Then I’ll have a better opinion of it.”

Quarterback Patrick Cowan observed practice while leaning on crutches.

He had a magnetic resonance test scheduled on his left hamstring Tuesday afternoon. The results were unavailable, but Dorrell said of Cowan’s injury, “It’s a little more significant than a day-to-day thing.”

McLeod Bethel-Thompson took reps with the first- and second-team offensive units and will probably be Ben Olson’s backup for the opener at Stanford on Sept. 1.

Dorrell has expanded his banned-from-talking-to-the-media list to include 1) any player who is practicing at a new position, 2) those who are hurt but go through a portion of practice and 3) those who are unable to participate in contract drills because of “soreness.”

Neither Ramirez nor Holmes was allowed to speak with reporters because the position switch “is not permanent yet,” sports information director Marc Dellins said.

Meanwhile, defensive end Bruce Davis and defensive tackle Brigham Harwell went through non-contact drills wearing red don’t-hit-me jerseys, and Pitre went through limited drills. Interview requests for all were refused.

Harwell has an injured right leg. Dorrell said Davis and wide receiver Joe Cowan were “sore.”

chris.foster@latimes.com