USC's Davis out vs. Arizona with ankle injury

USC's offense will be missing a key piece Saturday versus Arizona as running back Justin Davis won't play due to an ankle injury.

The Trojans leading rusher suffered a high-ankle sprain in last week's win over Colorado, and hasn't healed enough to play against the Wildcats. Head coach Clay Helton said USC will go with a running back-by-committee approach with Davis sidelined, using Ronald Jones II, Aca'Cedric Ware, and Dominic Davis.

"We've got three really quality runners," Helton told ESPN's Kyle Bonagura. "We're going to stick with our M.O. of knowing that our run sets up the pass and be a balanced offense. We have a lot of confidence in the three kids."

The Wildcats' rush defense has struggled in 2016, ranking ninth in the Pac-12, so despite Davis' absence, USC should still be able to move the ball on the ground.