OAKLAND -- A’s manager Mark Kotsay has developed a formula for late-game situations with a lead this season by relying heavily on a trio of relievers. Heading into Friday night, though, he knew strategizing for such a situation would be a bit more complex.

A three-run lead against the Rangers after six innings presented a seventh-inning spot typically reserved for Domingo Acevedo. But with the right-hander among the league leaders in appearances -- and having pitched three times over the previous four days -- Kotsay had already planned to give him the night off.

With Acevedo unavailable, the ideal workaround plan was for starter Cole Irvin, who’d limited Texas to two runs across the first six innings, to complete the seventh. That way, setup man Zach Jackson and closer Dany Jiménez could still line up for their usual roles with plenty of cushion. But once Irvin reached 93 pitches in the seventh on a one-out single allowed to Kole Calhoun, Kotsay opted for Justin Grimm as his first arm out of the bullpen.

Grimm, seldom-used in high-leverage scenarios this year, was thrust into a big spot and struggled. He retired just one of three batters faced, and by the time he walked off the mound as he was replaced by Jackson, Oakland’s lead shrunk from three runs to one. After Jackson allowed a game-tying double to Adolis García in the eighth, Jiménez surrendered three runs in the ninth, capping a rare off night from Oakland’s normally capable back end of the bullpen in an 8-5 loss to Texas at the Coliseum.

“In terms of the bullpen, they’ve done a great job all year,” Kotsay said. “This isn’t something that really happens. Our bullpen has come in and closed out games with leads. Not our normal night from the 'pen.”

Jackson entered the night having allowed just one earned run over his last nine outings. Meanwhile, Jiménez hadn’t allowed a run in eight of his previous nine games. Of course, perfection for any bullpen over a full season is an impossible task. Coupled with the heavy usage of both relievers -- Jackson’s 22 appearances are tied with Acevedo for second-most among American League relievers, while Jiménez was making his third appearance in the past four days -- an off night was bound to happen at some point.

“That’s baseball,” Irvin said. “As much as we’d like to be on our best every day, we’re not going to. I thought, offensively, we did enough to get the job done. It’s just one of those nights where it didn’t all click.”

Pitching himself into a jam in the ninth, Jiménez was one strike away from keeping the game tied heading to the bottom-half of the inning with the middle of Oakland’s order due up. Instead, a two-strike single by pinch-hitting Andy Ibañez that plated home a pair of runs was followed up with an RBI single from former A’s star Marcus Semien.

Given his early success this year, entering Friday with just one earned run over 18 1/3 innings, the A’s have strong reason to believe this could be just a minor blip on the radar for Jiménez.

The bullpen’s inability to finish was not the lone culprit in this loss. The A’s offense broke out for a five-run frame against Rangers starter Jon Gray in the third, ignited by Ramón Laureano’s RBI single and highlighted by back-to-back homers from Sean Murphy and Chad Pinder. But they were held hitless the rest of the way and the mood amongst A’s hitters was one of frustration, feeling they let a stumbling pitcher in Gray off the hook.

“We need to hit better, starting with me,” Laureano said. “The bullpen has been there a lot. As hitters, we’re not there as much as they are. If we can be as they are, we will be a way better team.”