UCLA football Coach Jim Mora finally reveals that Josh Rosen has been sidelined because of shoulder injury

UCLA Coach Jim Mora specified the issue that has sidelined quarterback Josh Rosen, explaining Monday for the first time that the quarterback’s return is contingent upon a nerve in his right shoulder beginning to fire again.

Rosen has not played since the final minutes of the Bruins’ loss to Arizona State on Oct. 8, sitting out games against Washington State and Utah.

It was apparent that Rosen had suffered injuries to his lower body and throwing shoulder against the Sun Devils, but Mora said he did not want to provide details until the shoulder injury was mentioned on the game broadcast Saturday.

“As a head coach, when one of our players has an injury, I’m not going to tell people what it is unless it’s very, very obvious because I don’t want the opponent to target it because I know that’s what they do,” Mora said. “As a coach, if you see an opponent and you know part of his body is hurt a little bit, it’s a vicious, violent game, but you go after it.”

Mora said that Rosen had resumed throwing, but “it just hasn’t gotten to the point where he can cut it loose yet.” It remained unclear whether the 1 1/2 weeks left before UCLA’s next game against Colorado on Nov. 3 at Boulder would provide sufficient time for Rosen to return.

“My understanding is that once it starts going he should be good pretty darn quick,” Mora said of the nerve in Rosen’s shoulder. “So hopefully that’s soon.”

Backup quarterback Mike Fafaul, who set school records with 70 passes and 40 completions on the way to a career-high 464 yards passing Saturday during UCLA’s 52-45 loss to Utah, said Rosen told him his shoulder was feeling better but that he remained frustrated by his inability to play.

“It’s tough for him,” Fafaul said. “He’s a competitor and he wants to be out there with his guys, but he’s been doing a great job supporting his team and being there for [us], especially me on the sidelines with everything, all the plays and the defenses. He’s done a good job of taking the pressure off me, I think, and just help me play relaxed.”

Westwood ho?

Mora said his message to high school recruits did not change with the Bruins stuck in the worst funk of his five seasons with the team. He said he continued to tout the school’s academics, athletic facilities, campus, location and the opportunity to play for UCLA at the Rose Bowl.

Suffering five close losses might not be as much of a drawback as it appears, Mora said.

“We’re right there and I think sometimes that appeals to a recruit—you know, you can be the difference-maker,” Mora said. “You can help us get over the hump.

“Plus when you bring kids in during the game weeks, they get to come sit in meetings and they get to be around the team in the locker room and they feel the atmosphere and I’m not sure that the result is always the decision-maker for them. It’s more the feeling they get when they’re on campus, and so it was a successful weekend in terms of that.”

Quick hits

Mora said that UCLA remained committed to running the football despite calling only 10 running plays against Utah: “I believe that you aren’t going to really win big unless you’re able to run the football.” Mora said that tailback Nate Starks has knee tendinitis “and he’s been struggling” and tailback Soso Jamabo is dealing with shoulder and ankle injuries. Jamabo had one carry against Utah and Starks did not play.

ben.bolch@latimes.com

Twitter: @latbbolch