ANAHEIM -- The A’s are pleased with the way closer Blake Treinen is progressing from a rotator cuff strain in his right shoulder.

The right-hander threw 20 pitches off flat ground before Thursday’s series opener against the Angels. It was the first throwing Treinen has done since landing on the 10-day injured list on Sunday. Treinen is expected to take a break from throwing on Friday, before advancing to throwing off a mound in a bullpen session.

“He felt good. He let it go for the first time, and we’ll probably give him a day off or so and look to get him on the mound,” A’s manager Bob Melvin said. “As far as the progression goes, I think we’re on a good pace.”

Treinen would be eligible to return from the IL on Wednesday for the second contest of a three-game series vs. the Twins at Oakland Coliseum. Given a full stint on the IL, the A’s are hoping the extra rest can help Treinen return to his 2018 All-Star form. He has a 4.08 ERA through 30 games while converting 16-of-18 save opportunities this season.

Chapman the All-Star?

All-Star Game starters were announced with the conclusion of the first Google MLB All-Star Starters Election on Thursday, a process that A’s third baseman Matt Chapman was not in the running for after being left out of the group of three finalists. All-Star reserves will be announced on Sunday at 2:30 p.m. PT on ESPN, and Melvin is hoping Chapman does not get snubbed for what he feels would be a second time.

“I’d be surprised if he didn’t make it,” Melvin said. “You look at the traditional numbers, and he’s on pace for almost 40 homers and 40 doubles. He’s the best defensive player in the game, the analytics will show you that. You look at his total bases, and he’s a couple below [Mike] Trout. It’s very All-Star worthy.”

Chapman has been making his own case for a first career All-Star selection over the past two weeks, as he entered Thursday on a 13-game on-base streak. Over that stretch, he slashed .354/.436/.708 with 10 extra-base hits and 12 runs scored.