LOS ANGELES — USC freshman quarterback Matt Barkley could not throw passes for the second consecutive practice Tuesday, increasing the chances that Aaron Corp will start at Washington on Saturday.

Coach Pete Carroll continued to say Barkley is “day to day” because of his bruised throwing shoulder and wouldn’t say when he would need to return in order to play.
Barkley said the injury has progressed since he initially suffered it last week at Ohio State. But when Barkley tried to throw Tuesday morning, “it was pretty bad,” he said.
“I can’t really bring my shoulder back,” Barkley said. “It’s hard to throw without doing that.
“It has gotten better. I’ve gotten a lot more movement. I thought I was going to be able to throw today. ... But when I tried to actually do it, to do a fast throwing motion, it hurt.”
Barkley is treating the injury with inflammatory medication and ice. He has missed only one game in his career, at the end of his freshman year at Mater Dei High, so watching Corp take the first-team reps the past two days was an unusual experience.
Corp pronounced himself good to go — “I’m ready,” he said — and Carroll sounded relieved to have such a strong fallback option. Corp came into training camp as the No. 1 quarterback before suffering a cracked left fibula Aug. 10.
“Fortunately, we have a tremendous alternative at the quarterback spot,” Carroll said. “We know Aaron can play. We don’t have any question on that at all. If the situation wasn’t that, in a couple days we might be thinking different.”
MAYS UNCERTAIN TOO
Unlike Barkley’s situation, Carroll said senior safety Taylor Mays (knee) definitely could play even if he couldn’t practice all week.
“It’s a totally different situation and circumstances,” Carroll said. “He’s been here for four years. He’s been playing the defense forever.”
Mays, who has a Grade 2 sprain of the medial collateral ligament in his right knee, worked exclusively on the side Tuesday and didn’t run. He also spent some time getting used to a brace he’d have to wear if he did play.
Mays said the brace would prevent further damage and that his participation would depend on pain tolerance. He added that he wouldn’t play if he didn’t feel “physically ready.”
If he were to sit out, it would mark the first missed game in Mays’ college career. Playing with a brace also would be a first.
“I played with braces on my teeth but not a knee brace,” Mays said. “This is clunky. I feel like an offensive lineman.”
Drew McAllister is on track to start if Mays can’t go. McAllister worked with the first team after missing last week because of a sore hip.
NOTES
The coaches moved Marshall Jones from cornerback to safety as a contingency with the travel roster limited to 64 players in Pac-10 play. ... Left tackle Charles Brown remained out because of illness.
Butch Lewis would start if Brown can’t return in time. ... Carroll turned 58 on Tuesday.