There are limits to what they can do

From a USC player’s standpoint, there might be one slightly positive side effect from NCAA sanctions and subsequent transfers and releases that have reduced the Trojans’ roster to 70 scholarship players.

The days of agonizingly long, full-pad double-day workouts are apparently over.

The limited number of players -- 15 under the allowable maximum -- and the risk of injuries that could deplete it further convinced Coach Lane Kiffin to change the format of two-a-day practices during training camp.

Instead of two full-contact workouts, the Trojans on Tuesday went through a two-hour morning practice without pads and then returned eight hours later for a full-pads practice.

It was the first of four double-days that are scheduled for the next two weeks.

“It just wouldn’t be smart to do it the other way,” Kiffin said. “It may make you feel better because we think we’re getting tougher but we’ve got to have enough bodies to play.”

From the time USC learned of its penalties, which include a reduction of scholarships that will affect the roster for years, Kiffin has talked about managing practices as an NFL team would.

USC’s usual training-camp schedule includes an afternoon workout that follows a morning “walk-through,” which is essentially a practice that under NCAA rules cannot include footballs or other football equipment.

On Tuesday, the Trojans left shoulder pads in the locker room and conducted their morning workout as if it were a walk-through, but with footballs.

“I wouldn’t have done that a year ago,” Kiffin said. “I would have come in and [said] ‘we’re going to be tough and physical no matter what’ and beat everybody up -- and we would have ended up with [only] five linemen by [Tuesday night’s] practice.

“I don’t think toughness is an issue with this team right now. I think we established that in the spring. We just have to continue to build on that and we have to be really smart at it.”

Players are happy about the adjustment.

“It’s a good idea, but guys have to come out here and make sure they pick up the pace full-tempo,” said senior running back Allen Bradford, who is going through his fifth training camp. “I think it’s going to save our legs a lot.”

Punitive measures

Freshman running back Dillon Baxter and freshman receiver Markeith Ambles spent all of USC’s morning practice rolling on the turf.

“They were late for something,” Kiffin told reporters afterward. “And so unfortunately that happens a lot of times with freshmen. They miss something by a few minutes and so we obviously want to set the tempo on what that means. And so they ran for two straight hours out here today, as you guys saw, a lot of tough stuff. And hopefully they learn from that like guys have in the past.”

Ambles participated in the evening workout, but Baxter was still relegated to the sideline where he performed more punitive drills. Asked afterward why Baxter was still being punished and doing exercises while Ambles participated, Kiffin told reporters:

“There’s just things that you have your opinion on of whether people make mistakes, whether people make choices on purpose. And so I felt Markeith, it was more of a mistake and I felt Dillon’s was more severe.

“I hope it’s a good lesson for him to learn. Now he’s gone about 4 hours 15 minutes, he’s been rolling and doing all those exercises today and lost out and all those reps. There was some really important stuff we put into today for him that he lost out on. So I’m hoping he’s learned his lesson.”

Kiffin said Baxter would return to practice Wednesday.

Upon further review

After reviewing tape of Sunday’s scrimmage, quarterback Matt Barkley said he had three misreads but was otherwise pleased.

Barkley’s training camp experience this year is far different than 2009.

“I just remember staying up late copying down plays after plays after plays trying to learn the offense,” said Barkley, who on Tuesday had a pass intercepted for the first time since training camp began -- by cornerback Torin Harris on a long pass intended for freshman Robert Woods.

Quick hits

Backup quarterback Mitch Mustain also suffered his first interception of camp, by freshman cornerback Anthony Brown on the last play of practice. . . . Safety Drew McAllister, who sat out spring practice after having surgery on his left hip, might undergo an MRI exam for discomfort in his right hip.

gary.klein@latimes.com

twitter.com/latimesklein