Third baseman makes 2 strong plays before error

ANAHEIM — Racking up five homers and nine runs should have done the trick Friday for the A’s.

But the Angels kept charging back, and finally, one of Oakland’s most reliable assets did not come through: Defensive whiz Matt Chapman made a game-changing error in the seventh inning and the A’s — who’d led the entire way until that point — wound up losing 13-9.

“It’s frustrating, especially defensively — something I take pride in,” Chapman said. “I wanted the ball hit to me in that situation . ... It’s tough not to think that that one’s on me.”

ANAHEIM — Daniel Gossett already was tabbed for demotion after Friday’s game because the A’s need the roster spot for outfielder Trayce

Thompson, who will join the team Saturday.

Gossett didn’t help his cause much any in his start against the Angels, either. He gave up five runs in 31⁄3 innings, running his ERA in two starts to 11.05.

He packed up after the game, heading to Triple-A Nashville. “I’ll go down there and finetune everything and come back ready to go,” he said. Gossett served up Shohei

Ohtani’s third homer in three games at Angel Stadium. The Angels then added four runs in the fourth, an inning in which the A’s defense factored: Andrelton Simmons drove in one run with a double, putting two men in scoring position for Luis

Valbuena, who hit a rocket up the middle. Shortstop Marcus

Semien was shifted in that direction, but the ball hit off his glove and both runners scored. Semien threw home, ill advisedly, allowing Valbuena to take third. Yusmeiro Petit took over with one out and, because Valbuena had taken the extra base he was able to score on a

Martin Maldonado single. “Too many hittable pitches,” Gossett said. “Stuff that’s completely out of the zone, nothing competitive. The quality of pitches wasn’t there.”

With days off Monday and Thursday the A’s don’t need a fifth starter until April 17, when they’re likely to call up Trevor

Cahill. Cahill, signed during spring training, makes his first start for Nashville on Saturday.

Triggs ready to go: Starter Andrew Triggs said he plans to mix his changeup in a little bit Saturday at Angels Stadium after scrapping it his previous time out. He liked the pitch during spring training and would like to incorporate it if it’s behaving.

“In a perfect world I’d like to throw a few more changeups and mix in some cutters, but that’s something you kind of go with in the moment when you see what’s working, what’s getting swings,” he said.

Triggs went 2-0 with a 0.77 ERA against the Angels last season and has a lifetime 1.06 ERA against them.

Briefly: Starter Daniel Mengden, who took a line drive off his right heel Thursday, and utility player Chad Pinder, who slightly hyperextended his left knee, were both “a little sore” Friday, according to manager

Bob Melvin. Neither injury is considered serious . ... Ryan

Dull (shoulder) worked two innings in a rehab assignment with Nashville and allowed three hits, a walk and one run with one strikeout. Susan Slusser is a San Francisco Chronicle staff writer.