With Rosenthal idled, bullpen roles are fluid

Roles in the A’s bullpen remain in flux 10 games into the season. That was evident in two wins in Houston for a unit that has sustained several injuries.

On Friday night, manager Bob Melvin had lefthander Jake Diekman warming in the top of the eighth of a 11 game with Yordan Alvarez, a lefthanded hitter, due up in the home half. After Matt Olson’s threerun homer, Melvin flipflopped and brought in Lou Trivino for the eighth, saving Diekman for the ninth.

On Saturday, Diekman entered in the seventh inning with the A’s leading 62, a runner on and lefthanded hitter Michael Brantley due up. Diekman followed Sergio Romo, who had faced four batters, hitting one and allowing an RBI double. Diekman allowed an RBI triple to Brantley but got four outs.

With a 73 lead, Melvin turned to J.B. Wendelken in the ninth.

Melvin said a smaller lead would have complicated things. He did not want to use Trivino or Yusmeiro Petit, who had each pitched three of the previous four days, but might have reconsidered in a tight spot.

“If there were a couple (runners) on I probably would’ve used one of those guys,” Melvin said.

Losing Trevor Rosenthal to injury has left the A’s without a clear choice at closer. They did not have a lead to protect in late innings until Friday, however, and have not faced a save situation in 10 games. Diekman is an option to close, but Melvin showed Saturday he will deploy the lefthander before the ninth if matchups require. Trivino could warrant consideration if he keeps pitching well. Wendelken retired three batters, striking out two, on 11 pitches Saturday.

“J.B. did a great job,” Melvin said. “When you haven’t been in that role before, pitching the ninth against a team like this, you go 123, that’s going to do a lot for his confidence.”

Big swing: Seth Brown’s first bigleague home run Saturday was a long time coming. Brown has 92 in the minors, including 37 at TripleA in 2019. His 424foot blast off Ryne Stanek came in his 102nd majorleague plate appearance.

“I’m happy for him,” Melvin said. “The only thing he doesn’t have on his resume is a homer for a guy that really is a homerun hitter, so I know that takes a lot of pressure off him.” Briefly: A.J. Puk (biceps strain) has yet to resume throwing and will spend more than the minimum stint on the injured list. “Ten days is not going to work as far as him being back,” Melvin said. … Mitch Moreland (hamstring) could be used to pinchhit in games at Arizona. The A’s will be off Wednesday: “Then hopefully after that we’re closer to getting him in on a regular basis,” Melvin said.