Receiver Marqise Lee was held out after suffering a left knee injury.
So evaluating USC after its first spring scrimmage at the Coliseum on Saturday was difficult.
But this much appears evident after the first week of practice:
•Third-year sophomore Cody Kessler will seize every opportunity to challenge Wittek for the starting quarterback job, and freshman Max Browne is improving every workout.
•Center Max Tuerk is a work in progress after making the transition from tackle and guard.
•USC's defense will play a much more aggressive, blitzing scheme under new defensive coordinator Clancy Pendergast than it did under Monte Kiffin.
•Freshman defensive back Su'a Cravens is in the mix for playing time in the fall and other early enrollees could be as well.
"As a whole, I like what I'm seeing," said Lee, who twisted his knee while catching a touchdown pass from Kessler in a drill. "We need to improve practically everything, but that's what spring ball is for."
Lee was scheduled to be evaluated further but said he would return for practice Tuesday.
Wittek was injured while serving as the holder during a kicking drill. As he stood to try to pick up a ball that was snapped low, another player rolled up on his leg.
Wittek said he would probably have an MRI exam but expected to return this week.
Meantime, Kessler completed 12 of 15 passes for 192 yards and Browne passed for the only touchdown during the 52-play scrimmage that was dominated by the defense.
Coach Lane Kiffin said he was pleased with the work of the defensive staff and was not overly concerned about the snap-exchange problems that led to fumbles and timing issues on offense.
"It's a long ways till we play a real game," he said.
It is too early to make any determinations about the quarterbacks, Kiffin said, but Kessler clearly enjoyed a solid week.
"I don't know if it's just the energy of the first week of spring ball or it's just the new mind-set that we have for this team," Kessler said, "but the competition level has just been amazing."
Browne completed two of seven passes for 48 yards, 43 coming on a touchdown to receiver Nelson Agholor. Kiffin also praised Browne for throwing the ball away on one play rather than taking a sack.
"Kids that age — it's hard to just even call a play and get out of the huddle, let alone execute," Kiffin said. "So I think he's doing well."
Said Browne: "That's the first time I really saw a live rush. I've still got a long ways to go, I'm still making mistakes, but I felt like I definitely grew as a QB."
Linebackers Hayes Pullard and Lamar Dawson, linemen Morgan Breslin and Devon Kennard and Cravens were among the defensive players that stood out playing in Pendergast's 5-2 scheme.
"Everybody has been recruited here because of speed and physicality," Pullard said. "We're just out there being disciplined."
Fullbacks Soma Vainuku and Jahleel Pinner are improving, Kiffin said, "and they need to. We got no production from that position last year" compared with 2011, when Rhett Ellison and Ross Cumming played the position.… Receiver George Farmer caught three passes for 74 yards, Agholor three for 60. … USC resumes practice Tuesday.