Mustain steps up in off week

USC’s off-week practices provided the showcase, as planned, for younger players hoping to impress coaches.

But junior quarterback Mitch Mustain also took advantage of the opportunity and might have positioned himself to become Matt Barkley’s backup for the seventh-ranked Trojans’ Oct. 17 game at Notre Dame.

On Friday, after Mustain completed 10 of 12 passes and threw for two touchdowns during an early morning workout that was conducted without pads, Coach Pete Carroll declined to say whether the former Arkansas starter had overtaken sophomore Aaron Corp as the Trojans’ No. 2 quarterback.

Any decision about a switch would probably be made on Monday when the Trojans return to practice after this weekend’s open date.

“He’s making a big move,” Carroll said of Mustain. “He’s throwing the ball really well. In general, he’s just picked up his game considerably. You can’t help but notice it.”

Mustain has been the odd man out in the quarterback discussion since early last spring, when Corp established himself as the starter and Barkley wowed Carroll and first-year quarterbacks coach Jeremy Bates.

After Corp suffered a knee injury early in training camp, Barkley took nearly every first-team snap and opened the season as the starter.

Corp started against Washington after Barkley suffered a shoulder injury against Ohio State, but the freshman came back and has played well the last two games.

Meantime, Mustain had been relegated to third-team reps and is also practicing as a punter.

But Mustain performed well in practice before the game against California and he played even better this week.

“He’s really strong-arming the football,” Carroll said. “I thought his shoulder or elbow was bothering him all through camp. . . . He’s back.”

Big impression

No first-year player had a better week than freshman cornerback Torin Harris, who intercepted another pass on Friday and also blocked a field-goal attempt.

Harris is on track to redshirt, but his future looks bright.

“I can’t slack off,” Harris said. “I have to get better even though I’m not playing. I want to compete for playing time next year.”

Johnson update

Tailback Stafon Johnson is expected to be released from the hospital in a few days, but he will be required to undergo multiple outpatient procedures as he continues to recover from throat injuries suffered in a weightlifting accident, doctors said Friday.

Drs. Jason S. Hamilton and Ryan F. Osborne operated on Johnson after the Sept. 28 accident.

“Though it remains far too early to make any predictions regarding the long-term function of his larynx, he has shown great strides in his initial recovery,” the doctors said in a statement. “He has an amazing attitude and a will to overcome all obstacles presented during this difficult time.”

More than 70% of Johnson’s larynx was injured in the incident, which occurred in the weight room at Heritage Hall.

“Put simply, the voice box was crushed and the upper portion was separated from the lower portion,” the doctors said.

Johnson was outfitted with a feeding tube from his nose to his stomach, and a tracheostomy tube to help him breathe.

The nasogastric tube will be replaced with a gastrostomy tube, which will be “far more comfortable for Stafon and allow him to maintain the nutritional balance needed during his recovery,” the doctors said.

Several USC players visited Johnson at the hospital on Friday.

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gary.klein@latimes.com

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