Kenny Bigelow said he lost three pounds after a haircut.
In the off-season, the 6-foot-3 defensive lineman cut off dreadlocks he had worn since the fourth grade.
The third-year sophomore is down to 285 pounds from the 310 he was listed at last season, which he spent sidelined after knee surgery.
"After the injury I had to look for a way to redefine myself," he said. "It was a way to boost my confidence."
Bigelow returns in time to compete for a role after the departure of Leonard Williams.
"Everyone is chasing that spot," he said.
Bigelow was considered a top recruit in 2012 out of Eastern Christian Academy in Elkton, Md., but he has yet to play at USC.
"I can't wait," he said. "That's what I came here for."