Angels ace Garrett Richards’ return is an open-ended waiting game

Garrett Richards and the Angels have no idea when he can return to pitching. The nerve irritation within his right biceps has not abated since it was diagnosed April 7, so he and the team can only wait.

“There’s no timetable,” Richards said Sunday. “With nerves, they have a mind of their own. They regenerate at their own pace. It’s mainly just staying strong, staying in shape, and waiting for this thing to regenerate.

“It sucks, but it is what it is.”

Richards exited his first start of the season on April 5 with what was initially diagnosed as a biceps cramp, then a strain within the biceps muscle. At that time, sources told The Times the initial MRI examination showed nerve irritation in that muscle. On Saturday, the Angels moved Richards to the 60-day disabled list because of that irritation, rendering him ineligible to return before June 5.

He has not thrown a baseball since that first start. The team tests his biceps regularly, via methods general manager Billy Eppler has said he will not reveal. When the strength improves enough, he’ll resume throwing.

“I feel good, other than the fact that my biceps just isn’t strong right now,” Richards said. “The nerve being irritated is contributing to the pace that my strength is coming back. Obviously I’m disappointed considering all the work that I put in to get back from last year, but it’s nothing I haven’t gone through before.

“The nerve isn’t helping my bicep contract and fire, which is why the lack of strength is there. But we’re confident that with time it’ll come back to normal.”

Richards made only six starts last season before exiting a May 1 start with what was initially diagnosed as dehydration, and then the torn ulnar collateral ligament in his right elbow that ended his season. He received a stem-cell injection that regenerated the ligament and allowed him to pitch in instructional league games in October. He built up his stamina in spring training.

“You feel so good coming into the season,” he said. “You have a good spring. Everything is back to normal, kind of. You start feeling more and more like yourself. And then you have something like this come up. It’s disappointing.”

Two weeks ago, Richards was convinced he’d be back pitching by now. He’s now far less confident, but trying to keep his perspective in a productive place.

“There are a lot of positives working in my favor,” he said. “But it’s hard to look at the positives when you have so much negative going on.”

Still, Richards’ elbow remains structurally sound, a source of continued encouragement for him.

“My elbow and my shoulder have never felt any better than they do right now,” he said. “Why wouldn’t they, with all the rest that I’ve had?”

Short hops

The Angels promoted right-hander Brooks Pounders from triple-A Salt Lake and designated right-hander Kirby Yates for assignment, switching out relief arms. Asked when he received notice that he had been called up, Pounders said he did not know. … Infielder Luis Valbuena will begin a minor league rehab assignment Monday with Class-A Inland Empire. He’ll play third base, first base and some designated hitter over five to seven games. Valbuena suffered a hamstring strain in March. … Right-hander Jesse Chavez will start Tuesday against Oakland instead of right-hander Ricky Nolasco, who was scheduled. Manager Mike Scioscia said Nolasco is “working through some mechanical issues.” … The Angels traded outfielder Ryan LaMarre to Oakland for cash or a player to be named.

pedro.moura@latimes.com

Twitter: @pedromoura