ARLINGTON -- Rangers pitcher Mike Minor prepared for Saturday’s start against the Athletics at Globe Life Park like he always does. He sat down with the starting catcher and thoroughly went over the game plan.

Jeff Mathis was the starting catcher. His backup, Jose Trevino, had the night off and was not in that meeting.

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Then, after two innings and a three-run lead, Minor found himself throwing to another catcher. Mathis had to leave the game with a lower back strain and Trevino took over. The transition did not go well.

Minor gave up a season-high seven earned runs, all coming off home runs, in an 8-6 loss to the Athletics on Saturday night. Minor had allowed just three homers in his last seven starts -- 49 2/3 innings -- before running into the A's.

“I felt all right,” Minor said. “I thought they hit some pretty good pitches. I don’t know, I thought about it. ... I didn’t know why they were hitting some pitches that on the scouting report they weren’t supposed to. I didn’t know if I was throwing pitches in sequences that were very telling to them.”

The catching change had an impact in the third with the Rangers holding a three-run lead. Marcus Semien and Ramon Laureano both singled with one out, bringing Matt Chapman to the plate. Minor threw a first-pitch slider and Chapman hit it out to left field to tie the game.

“I thought he called slider in,” Minor said. “There was a guy on second, so I looked at him and when I lifted my leg and turned, I saw [Trevino] bounce to the outside, and so I kind of flipped the ball in there and he happened to hit a home run.”

Minor was able to get out of that inning with the score still tied. Between innings, Trevino got a crash course on the game plan.

“Mid-game game change and a young guy back there,” Minor said. “I think it might have sped up on him a little bit. Something to learn from.”

Mathis has caught Minor most of the season. The left-hander, however, had thrown to Trevino in his last two starts and won both, throwing 7 1/3 scoreless against the Yankees on Sept. 2, and allowing two runs in eight innings against the Orioles on Sunday.

But it’s a little different when being forced to enter the game cold without proper preparation.

“It's tough, but I've just got to be better at it,” said Trevino, who admitted he could have done things differently.

“Yeah, plenty of things,” Trevino said. “Sequences, getting on the same page, sign stuff. Yeah, that's no excuse, though. I faced [Oakland] yesterday, I saw them yesterday. So I need to do a better job of that. Just weren't on the same page for a little bit. I just need to do a better job of that."

Minor also gave up two-run home runs to Josh Phegley in the fourth and Mark Canha in the fifth that put the Athletics ahead for good.

There were a few things that stood out from Minor’s five innings of work. Minor got whiffs on just two of the 14 swings against his changeup. That is a 14 percent whiff rate, far below his 31.1 percent average on that pitch this season.

The other two big flies allowed were on fastballs. It’s only the second time this season he’s allowed multiple homers on his four-seamer in the same game.

The Chapman home run and a double by Sheldon Neuse both came on sliders. It’s just the second time this season he’s allowed multiple extra-base hits on sliders.

“I’ve pitched them the same for the last two years,” Minor said. “I’ve only faced them once this year so I thought going at them the same way would work, but I felt they were looking for those pitches in that area. That’s kind of what happened, some of the pitches they hit were not bad pitches in not bad spots, the right pitch in the right count and they hit it pretty well. I think I face them again the next time so I have to switch it up.”