Quick, guess which USC quarterback has thrown the most interceptions for the Trojans this spring?

It's not Cody Kessler, who has thrown zero, or fellow redshirt freshman Max Wittek, who has thrown only a few. It's starter Matt Barkley, who, after his latest pick in Thursday's practice, has now thrown seven in eight practices this spring.

Coach Lane Kiffin is not worried, but he's not exactly pleased, either.

"We don't like it," Kiffin said Thursday. "But it's not the end of the world. As we get closer to game time we'll get him back to normal."

What can the mistakes be attributed to? Aside from sheer coincidence, which Kiffin seemed to think was a bit of the problem, the coach also offered two other reasons: (1) Sheer boredom and (2) A lack of talent around him.

"I think, at times, he gets bored, which is normal, because we have so many guys out around him," Kiffin said. "I don't think it's the lack of reps -- I think it's more not having those guys to work with. He wants to go to that next level with guys, and so the guys that are there he's doing it and getting comfortable with them.

"But hopefully we'll get the rest of them back."

Kiffin joked he can't yet yell at Barkley because he could still declare for the NFL supplemental draft this summer. But he said more seriously that he's not worried about the interceptions because he already proved he could limit them in regular-season play.

Barkley threw just seven interceptions in the Trojans' 12 games last season.

"He's already shown he can have phenomenal ball control," Kiffin said, "so you're not as frustrated as you normally would be with a guy forcing it down the field because you feel also some of his pain because his weapons aren't out here.

"They won't be bad habits."