Much like Sean Manaea the night before in Oakland, Mike Fiers appeared to be a bit rusty in the early goings of Tuesday’s outing against the Giants at Oracle Park.

Command seemed to be an issue in the A’s 4-2 loss, primarily through the first two innings as Fiers surrendered a pair of solo home runs and only threw 23 of his 41 pitches for strikes. Fiers appeared to get back on track toward the end of his outing, though he was critical of his overall performance in a start that ended with him allowing three runs on three hits and two walks over 3 1/3 innings.

• Box score

“It didn’t go as well as I wanted to but I got my work in,” Fiers said. “I made it tough on myself being pretty wild. I’m just glad this game doesn’t count. I just have to lock it in.

“I wasn’t throwing the ball exactly where I wanted it to. Just a little erratic. I just have to find how to settle down when those times come.”

Part of the early struggles may have been a result of Fiers working with rookie catcher Austin Allen, who is a newcomer to the club after arriving from the Padres in a trade this offseason. The two got mixed up on signs a couple of times through the first two frames.

“With Mike’s stuff, he pitches a little backwards and is unpredictable at times,” A’s manager Bob Melvin said. “That takes a little to get used to. Next time they’re matched up, I think Mike knows that he’s got to go with what he feels. That’s typical with young catchers. Mike is a veteran, so that shouldn’t be a problem.”

There were some bright spots for Fiers. His offspeed pitches helped him get out of trouble, using his curveball as the putaway pitch on all three of his strikeouts. Finishing with 67 pitches, Fiers will get bumped up to around 75 to 85 pitches for his first start of the regular season, which will come Sunday against the Angels at the Oakland Coliseum.

“He was fine,” Melvin said of Fiers. “He’s a little frustrated with a couple of pitches, but we got him where we wanted to.”

After Joakim Soria relieved Fiers to finish the fourth, Chris Bassitt took over and finished out the game for the A’s with four innings of one-run ball, limiting the Giants to three hits with five strikeouts.

The strong relief outing was a positive sign for Bassitt, who will begin the season in the starting rotation and is scheduled to start Monday’s opening series finale against the Angels.

“Good command of his fastball and a real good slow curveball,” Melvin said of Bassitt, who did not walk a batter in his four frames. “He didn’t even get to his pitch count. That means he’s commanding with all his pitches and it’s good to see. His last two times out he’s been terrific. I know he feels good about going into the season.”

Pinder stays hot

The A’s offense struggled to get much going over their two exhibition games against the Giants, but Chad Pinder carried his hot hitting from Summer Camp over to Tuesday night. After sitting out Monday’s game, Pinder got the start at second base on Tuesday and blasted a pitch from Conner Menez that bounced off the top of Oracle Park’s high brick wall in right-center for a two-run triple.

The triple was challenged by Melvin, who thought the ball had cleared the wall and hit off the seats just above it. But the call stood after the play was reviewed by umpires.

“I couldn’t tell with me slipping at first base. I couldn’t see where the ball went,” Pinder said. “My teammates were saying it was a home run. It’s all good. But on Friday, I want that one.”

Through the two games, the A’s registered just four runs on six hits. It probably didn’t help that the Giants used 18 pitchers over 18 innings, though Melvin said that was no excuse.

“Maybe that has something to do with it, but we would have liked to have had a little better offense in these games,” Melvin said. “We have a good offensive team, so it’s not concerning. But we just didn’t do a whole lot.”

Allen makes the squad

After the game, Melvin revealed that Allen made the Opening Day roster as the backup catcher to Sean Murphy. Jonah Heim, who was also in contention for that role, will be a part of the A’s three-man taxi squad to begin the regular season.

“Either way, it was going to be a good decision,” Melvin said. Both guys impressed. A little more experience and power with Austin, but Jonah is a guy that is going to be here. He never looks overwhelmed. It was a tough call, but this is the way we’ll start.”