The injury means sophomore backup Martail Burnett will switch ends of the defensive line to replace Ledbetter, with junior-college transfer Soli Lefiti and redshirt freshman Pate Moleni competing to fill the vacancy left by Burnett.
"I'm more worried about the kid right now than anything else," defensive coordinator Gary Andersen said. "We have to step back from Utah football for a little bit and worry about Marquess Ledbetter."
Andersen said the surgery went well, but that Ledbetter will need months to heal and recover. The Utes will apply to get Ledbetter an extra year of eligibility, Andersen said.
A 6-foot-2, 265-pound native of Mississippi, Ledbetter was among five returning starters on defense and an all-conference candidate, after making 4 1/2 sacks for the Utes - including two in the Fiesta Bowl victory over Pittsburgh - last season.