Arizona running back Nic Grigsby stood on the sideline in street clothes last Saturday as his team dismantled visiting Washington State.

The junior and the Wildcats’ leading rusher may very well play a similar role this weekend as No. 18 Arizona (6-2, 4-1 Pacific 10 Conference) faces off with California (6-3, 3-3 Pac-10).

This situation presents a dilemma for the Wildcats, who also have seen injuries impact second and third running back options Keola Antolin and Greg Nwoko.

Luckily for Arizona, Saturday’s 41-point beat-down against Washinton State gave the coaching staff a chance to evaluate its depth at the running back position, and thanks to the strong efforts of senior Nick Booth and freshman Taimi Tutogi, they were impressed.

“”All the guys did a very good job for us (Saturday),”” said offensive coordinator Sonny Dykes. “”Booth did some good things. He just needs to be consistent. And Taimi came in and gave us a little pop when we were trying to run the power game and did a good job doing that.””

After carrying the ball only 15 times all of last season, Booth eclipsed that mark Saturday with 88 yards on 18 carries in addition to collecting a touchdown. The senior, who came into the matchup with WSU with just 10 carries on the year, finished the day as the team’s leading running back in both yards and carries.

Booth’s day was the most productive of his Arizona career, as the 6-foot-2, 221-pound back has been bounced around throughout his two seasons in Tucson. Prior to the start of last season, Booth seemed poised to assume the number two position, before Antolin stole it away right before the season began. This season, with the addition of Nwoko, Booth has fallen to the number four spot and has not seen much of the field through Arizona’s first eight games.

“”I’m just trying to always stay prepared,”” Booth said. “”Coaches are always preaching that we need to be ready when we’re called upon.

“”It’s been hard (moving down in the depth chart) but coaches tell me to keep my head in place, and that I’ll get my chance and my opportunity as long as I continue to work hard. And that’s what I’m trying to do.””

While Booth took the majority of the carries Saturday, Arizona also threw H-back Tutogi into the mix in situations conducive to a power attack. The freshman, typically used as a blocker, received his first carries of the season against the Cougars. With his power, Tutogi took 11 carries and hammered his way to 50 yards and a late touchdown.

Although his primary role is to protect the quarterback and open holes for Arizona, Dykes suggested the freshman could see increased time with the football.

“”It’s possible,”” Dykes said of giving more carries to Tutogi in the future. “”But he’s still young so we don’t want to put too much on him and overload him. Because when you do that it impacts how he plays at fullback, and we really need him to play fullback really well.

“”But we’ll continue to mess around a little bit and see where it goes,”” he added.

With Nwoko likely back in the lineup this week, he and Antolin will be the primary rushers for Arizona. Nwoko sat out last Saturday’s game despite dressing while Antolin, who has been nursing an ankle injury, saw limited carries for 61 yards and a score.

But even with two of the Wildcats’ top running backs at least somewhat healthy, the chance Booth and Tutogi received last Saturday inspired competition throughout the running back core.

However, the added pressure in practice is nothing new to any of the backs and running backs coach Seth Littrell says he feels the ongoing competition does little to impact the cohesion of the group.

“”I think we’ve got a close group, and that’s a credit to those guys,”” Littrell said. “”I think when you’re around each other every single day, and you work together, and you’re in meeting rooms together and you critique each other, everybody knows that everybody has weaknesses and everybody has strengths. I think you’ve got to put your ego aside because this is a team effort.

“”No matter what position or where you’re at on the field, you have a role in helping this team win and I think each individual understands that.””