LOS ANGELES (AP) -- Southern California tailback Stafon Johnson had emergency throat surgery Monday after a weightlifting accident.
The senior who scored the No. 7 Trojans' go-ahead touchdown against Ohio State two weeks ago was bench-pressing when the bar slipped from his right hand and fell onto his throat.
"It hit him with a lot of force, and it hurt him," coach Pete Carroll said after the Trojans' brief practice Monday night. "No broken bones as far as I understand, but he's got some damage in there somewhere, and they're working it out, trying to figure out what it is."
Johnson is the Trojans' second-leading rusher with 157 yards, and he leads USC (3-1, 1-1 Pac-10) with five touchdowns. He led USC in rushing last season with 705 yards and nine touchdowns, but has evolved into the Trojans' short-yardage specialist this season behind starter Joe McKnight.
Carroll said Johnson "was OK," but couldn't speak, when he left the weight room for California Hospital Medical Center. Johnson's family and friends gathered at the hospital on Monday to await word on his surgery, which was still going on at 9 p.m. PDT.
"It is serious," Carroll said. "He did get hurt, so we don't know exactly what it is, and they're not going to know until they go through the surgery."
Johnson is just one of six tailbacks who get regular practice time with the Trojans, who visit No. 24 California on Saturday. The Trojans didn't immediately know how long Johnson would require to return from surgery.
Johnson had a spotter when the accident happened -- an assistant strength and conditioning coach was standing over him.
"I've seen players have the bar slip and fall onto their chest, but never in my 25 years of coaching have I heard of someone dropping a bar on their throat," said strength and conditioning coach Chris Carlisle, who was standing 10 feet away when the accident happened. "We're fortunate he was being spotted."
Johnson scored two touchdowns apiece against San Jose State and Ohio State, including that 2-yard run with 1:05 left to beat the Buckeyes. He added another touchdown last weekend against Washington State.
Johnson has carried the ball just 32 times this season, while also catching one pass.