Angels’ Jerome Williams still having medical tests

Jerome Williams believes the breathing problems that forced him to be hospitalized after Monday night’s 31/3-inning start against the San Francisco Giants were caused by “a mixture of asthma and anxiety.”

The right-hander rejoined the Angels on Wednesday but was put on the 15-day disabled list to clear a roster spot for Jered Weaver, who returned from a lower-back strain to start against the Giants.

Williams, who passed out in the clubhouse Monday night and was taken by ambulance to UCI Medical Center in Orange, was released Tuesday and returned to the hospital for more tests Wednesday.

He said he will undergo a stress test Thursday, but as of Wednesday, doctors found no signs of an irregular heartbeat or heart ailment.

“We’re just doing tests, trying to figure out what’s going on,” said Williams, who said he was “a little amped up” to face the Giants, who drafted him in 1999 and released him in 2005. “We should know more by the weekend.”

Williams does not take anxiety medication but has used an inhaler to manage his asthma in extreme heat or at high altitude. He said he hasn’t had an asthma attack “since I was 4 or 5 years old,” but he had trouble breathing during a start for the Chicago Cubs in steamy St. Louis in July 2005.

With Williams on the DL, Garrett Richards, who is 2-0 with an 0.86 earned-run average in four games, will remain in the rotation and start Sunday against the Dodgers. Dan Haren will pitch Friday night and Ervin Santana will start Saturday.

Follow the leader

Mike Trout’s eighth-inning walk Tuesday gave him enough plate appearances to qualify for the batting title, and the 20-year-old outfielder popped up on American League leaderboards, ranking second in average (.337) and third in on-base percentage (.397) before Wednesday.

“It’s awesome,” Trout said. “It’s really good to be up there, but it’s still a long year, and you want to stay up there and keep winning.”

Trout also leads the AL with 19 stolen bases despite not joining the Angels until April 28. Perhaps most impressive, he has scored 40 runs in 47 games, a pace at which he’d score 137 runs in 162 games.

“Getting on base and scoring are the most important things for me,” the speedy Trout said. “As a leadoff hitter, that’s what I base my game on.”

Premature celebration

Several Giants took note of the way Mark Trumbo flipped his bat after crushing a three-run triple off the center-field wall in the fourth inning Tuesday, but the Angels slugger said he wasn’t trying to show up the opponent.

“I thought it was a grand slam and got caught up in the moment a little bit,” Trumbo said. “I keep everything pretty much under the radar. I wouldn’t have done that if I knew it was going to hit the wall. But I’ve hit a few home runs here, and if I hit a ball flush like that, I think it will go out.”

Short hops

Reliever David Pauley, who was designated for assignment Monday, was claimed off waivers by the Toronto Blue Jays on Tuesday.

mike.digiovanna@latimes.com