USC's Kevin Graf in line to start at LT

LOS ANGELES -- USC Trojans offensive lineman Kevin Graf has been lining up at left tackle in winter workouts and appears in line to start at the position in the 2012 season.

The position comes with big cleats to fill and even bigger responsibility -- USC's previous left tackle, Matt Kalil, didn't give up a sack in 2011 and stands to be a top-five pick in April's NFL draft.

Graf, a fourth-year junior, started all 12 of the Trojans' games at right tackle last season. His main competition for the left tackle spot next season is gargantuan sophomore Aundrey Walker, who spent most of last season as a backup guard.

"I'm working at left tackle right now and [Walker's] on the right," Graf said Tuesday after the start of USC's coach-supervised conditioning sessions. "So we'll see what happens."

The 6-foot-6 Graf says he currently weighs 285 pounds and would like to get up to 305 come the fall. Walker is listed at 6-6, 375 pounds but has told reporters this offseason that he's down to 320 pounds.

Graf and Walker's competition will be one of a few prominent position battles during spring practice for the Trojans, including at fullback, strong safety, nose tackle and No. 3 receiver.

Spring practices are scheduled to start March 6.

Pedro Moura is a regular contributor to ESPNLosAngeles.com and covers USC football.