San Diego Chargers running back Ryan Mathews underwent surgery to repair a broken collarbone Friday afternoon.
Mathews suffered the injury on his first carry of San Diego's first preseason game against the Packers on Thursday night.
"I wouldn't expect it to be any different than what we said," said Turner on Friday. "We're probably looking at four weeks if we're fortunate. It could go to six weeks."
Turner also said speculation that the injury was either caused by, or somehow related to, a car accident Mathews was recently involved in is simply not true.
"If you look close at the play and how he fell, the way he used his arm to brace himself and the way his arm got twisted underneath, you can see how the injury would have happened."
The majority of the preseason rushing work will now go to a committee of backs, including Curtis Brinkley (who started the 2011 regular season finale in Oakland), Le'Ron McClain, Ronnie Brown, and Jacob Hester.
Turner said he likes the guys he has at the running back position and doesn't expect the team to make a move to bring in another player.