What’s more, backup running back Keola Antolin, who offers some of the big-play potential that Grigsby has, is questionable because of a shoulder injury that forced him out early in the second quarter of last Saturday’s game against Oregon. Antolin, however, was asked Monday about that, and he said, “I didn’t know that until right now.”

Antolin still has to be further examined before a decision is made.

Arizona likely will be down to third-stringer Greg Nwoko and fourth-stringer Nick Booth.

“It has hurt us,” offensive coordinator Sonny Dykes said, talking about dealing with chronic injuries to Grigsby and Antolin through the Pac-10 schedule. “We’ve not had as many big plays as we’re used to having around here.”

Also, slot receiver David Douglas is out for this week because of a thigh injury, Stoops said.

Arizona coach Mike Stoops said after Saturday’s 27-13 victory over UCLA that starting running back Nic Grigsby and third-string back Greg Nwoko each suffered sprains of the AC shoulder joint during the game.

For Grigsby, it’s an aggravation of an injury he has been playing with for a few weeks. He left the game in the first half. Nwoko left the game late in the third quarter and had his left arm in a sling as he left the field.

“How severe, to what degree, I will know more next week,” Stoops said.

Second-string back Keola Antolin, who didn’t practice late in the week and didn’t play in the first half as he was trying to rest an ankle injury, came in during the second half. He rushed 16 times for 77 yards and made what offensive coordinator Sonny Dykes called the play of the game.

Antolin gained 11 yards on a draw on third-and-10 from the UCLA 36 in the third quarter. Arizona scored on a 25-yard catch-and-run by Juron Criner one play later for a 20-6 lead.

“He still has been bothered by that ankle, but that’s the best he has looked in a while,” Stoops said. “It was good. we needed him. We needed to run the football.”

Fourth-stringer Nick Booth added a 6-yard touchdown run with 34 seconds left in the third quarter for the game’s final points.

Dykes joked that maybe some of UA’s receivers can help at running back; UA did have good luck running several fly sweeps to its wideouts (a combined nine carries for 95 yards). But running back depth could really be an issue for the next game — vs. Washington State on Nov. 7 — and beyond.

Who is behind Booth on the depth chart?

“Open tryouts for running backs,” Dykes joked.

You have to go down to Kylan Butler and Daniel Jenkins, both of whom are true freshmen who are redshirting.

“Hopefully, we won’t get to that point,” Dykes said. “We’ll probably get those guys some reps this week and see who we feel is a little bit further along, and go from there.”

Elsewhere, quarterback Nick Foles was suffering from the flu, which helps explain his mixed night. He threw three interceptions — two on deflected passes — and made a bad handoff exchange with Nwoko for a lost fumble on the first play of the second half. In general, he just wasn’t quite as sharp.

He threw a lateral that linebacker Akeem Ayers broke up and safety Tony Dye scooped up for a touchdown on a fumble return. Dykes said Foles had the option to call a run or a pass on that play, and should have called a run based on the defense.

“We kind of made a bad decision,” Dykes said. “The thing is, we’ve run a thousand of those this year and he’s made the (right) decision probably 98 percent of the time.”

Dykes said Foles seemed to wear down as the game went on, although Foles’ other numbers don’t look bad — 22 of 34 for 247 yards and two touchdowns.

“Probably didn’t play as well as he has been up to this point, but at some point, he was going to have to come back to earth,” Dykes said. “Tonight, he did. It was humbling. The good thing is he was tough enough to overcome it and make enough plays for us to have a chance to win. The defense, obviously, played fantastic.”

Speaking of that defense, it was without starting defensive end Brooks Reed again. Reed has missed almost all of the past four games because of an ankle injury. D’Aundre Reed, who has been playing with a broken hand, started the game in Brooks Reed’s spot, but aggravted the injury and came out in favor of Apai Tuihalamaka.

Stoops said the goal is to get Brooks Reed healthy during the bye week and especially have him ready to go for a rugged finish to the season — at Cal, vs. Oregon, at ASU, at USC.

“We’re trying to get Brooks back to full strength,” Stoops said. “The back end of our schedule, there is a lot there.”