USC's running back rotation remains a topic of discussion, debate and curiosity four games into the season.

Fans who felt that sophomore Stephen Carr was primed for a breakout campaign with Ronald Jones off to the NFL have wondered aloud about his usage so far, with the most recent game only adding to the unclarity of the rushing picture.

Senior Aca'Cedric Ware had led the Trojans in carries the first two games before the running game fell flat entirely at Texas, and while Ware was limited last week with a knee injury it was bruising redshirt-sophomore Vavae Malepeai -- not Carr -- who saw his opportunity increase with a team-high 13 carries vs. Washington State.

Even after Carr took the first two touches of that game for 6 and 50 yards, he received just one more carry until late in the third quarter. Overall, he finished with 8 carries for a season-best 77 yards in the win. Malepeai, meanwhile, also capitalized on his touches for 78 yards and 2 touchdowns.

It worked, but it didn't answer any questions as to the Trojans' plans for the position moving forward.

By the time the query got to USC offensive coordinator Tee Martin on Tuesday, when the team's offensive players and coaches are made available to reporters, well, it sounded like he had heard it enough already this fall.

"Well, Clay substitutes the running backs on the sideline during the game," Martin clarified, referencing head coach Clay Helton. "I think he does it based on the feel and how they're looking. I'm upstairs, myself and [running backs coach Tim] Drevno are upstairs, so he manages based on how he feels and what he sees."

So the question then went to Helton.

He noted that the Washington State game was "a little bit different" with Ware being limited in practice during the week, but he didn't overtly tip his hand as to how he might proceed with that rotation moving forward.

"Obviously, you want to get a guy going and get him cranked up," Helton said. "There are some situational things. I think Vavae has done a tremendous job of being a short-yardage goal-line runner. And even in the four-minute, I thought he did a wonderful job of running through linebacker and safety tackles. He's a load in between the tackles. Stephen is that home run hitter -- he's just what you saw on that opening drive, he busts out for 50 yards. And then you got Ced, who's an every-down back. All three are capable."

It will be telling how each of those three backs is used in the Trojans' game at Arizona on Saturday night, with Ware expected to be back healthy, Malepeai coming off a career-best game and Carr still perceived by most observers as the most dynamic of the team's rushers.

Carr leads the team in yards per carry at 5.9, despite not receiving more than 10 rushing attempts in any game.

Meanwhile, Helton had high praise in particular for Malepeai, who had just 5 carries combined the previous two games before his breakout performance Friday night. "I really feel he's become an every-down back," Helton said, and with 5 touchdowns already, it would seem Malepeai has at the least locked in a goal-line, short-yardage role.

For his part, Carr said "the running back rotation is just amazing," when asked about it after that last game.

As for Malepeai, he said he'll be ready for whatever his role is this weekend.

"We all kind of just feed off each other's energy," he said. "We have a saying where we just stay ready so we don't got to get ready, so by the time we're in we just do what we've been practicing all week. All the running backs work and we just try to get each other better. We all compete against ourselves and we just get each other better every day. ...

"We've all been getting opportunities in the backfield, so we're just trying to do the best as we can to maximize every opportunity we get."