The freshman, for the first time since arriving at USC last spring, appeared fazed by a situation on the field and performed poorly.
So Barkley, perhaps more than any player, is looking forward to this afternoon's scrimmage at Howard Jones Field.
Barkley said Friday that he has learned from Monday's five-for-18 passing performance.
"I just have to settle down," Barkley said. "I think I was looking downfield too much, and I think I've done a great job since really throwing to the backs more and getting quicker with my reads and learning to get completions when I can."
Barkley remains on track to possibly start the Sept. 5 opener against San Jose State at the Coliseum, but Corp continues to make a pitch to reclaim his spot atop the depth chart.
The third-year sophomore, who suffered a cracked left fibula on Aug. 10, practiced Friday in full pads for the first time since training camp began, performing well again in seven-on-seven passing drills.
Earlier in the day, Corp tested his left leg on an anti-gravity treadmill, which allows trainers to increase or decrease air pressure to counter the weight of the athlete running.
Corp said he ran for 12 minutes bearing 90% of his weight. He plans to increase the load if his leg does not swell.
Corp is hoping to be near full strength when the Trojans resume practice on Tuesday after two days off.
"I think I'll be mobile enough," Corp said before his treadmill workout. "I won't be running away from guys, but as long as I can slide in the pocket and maybe get out and throw on the run, I should be fine."
Coach Pete Carroll said he would not wait until the week before the opener to make a decision about the starting quarterback.
That means Corp must come out of a weekend of intense rehabilitation ready to go.
"It'll be really difficult, if he's not able to go full-speed next week, for us to go with him," Carroll said, adding, "There's no rush. We have to do this right to get him back when he's safe."
Corp intends to show he is ready.
"I want to come out there and make good decisions but I do want to come out and perform too," he said. "If I can rip a couple of touchdowns or whatever, that will be even better."
In the meantime, Barkley is scheduled to take all of the first-team snaps in the scrimmage.
Junior Mitch Mustain and senior Garrett Green will work with reserves.
"We're going to give Barkley all that and fill him up as much as we can," Carroll said.
End Wes Horton worked much of the day with the first-unit defense in place of Armond Armstead, who suffered a broken bone in his left foot on Thursday and underwent surgery on Friday. . . . Receiver Damian Williams participated in a few drills but remains mostly inactive because of a quadriceps bruise. . . . Cornerback Shareece Wright said he would have fluid drained from his right leg, which has resulted from a knee bruise. Carroll said Wright still faces an academic issue that could affect his eligibility. . . . Freshman safety Jawanza Starling made the hit of the day when he broke up a pass intended for freshman receiver De'Von Flournoy. . . . USC's annual "Salute to Troy" event will be held tonight on Cromwell Field. . . . The Trojans practice today at 9 a.m. and 3 p.m. The scrimmage begins at 3 p.m.