After three days of being sequestered inside their hotel in Houston because of a positive COVID-19 test by a member of the organization, the A’s have returned to some normalcy. The club flew home to the Bay Area on Tuesday night and took the field for the first time since Saturday for a workout at the Oakland Coliseum on Wednesday morning.

“It’s been tough,” manager Bob Melvin said. “It’s something we’re going to have to work through and understand that, at this point, there’s not much we can do about it. Just prepare for our next game.”

• Rest of A's-Mariners series postponed

The A’s expect to begin their three-game series against the Padres, scheduled to start on Friday at the Coliseum. It will be their first game since they played a doubleheader in Houston on Saturday. Before that they had not played since Aug. 26, as back-to-back games against the Rangers and Astros were postponed as forms of protest over the shooting of Jacob Blake by a police officer in Kenosha, Wis.

Unable to work out during their time in self-isolation, the A’s are doing their best to shake off rust by holding workouts at the Coliseum on Wednesday and Thursday.

“We have to be prepared for it. We have to go out there with the expectation to win come Friday,” Melvin said. “We’ll try to ramp up here in the next couple of days to prepare for that. But this season, in general, has been a mental battle as well. You see the standings and see how they are doing; there is a lot more that goes on behind the scenes this year than other years.”

That preparation will have to include readiness for a heavy workload for the month of September. Due to the various postponements, the A’s will have to play four doubleheaders over the final 20 days of the regular season. The first twin bill comes on Tuesday in Oakland against the Astros, the club that entered Wednesday trailing the A's by three games for first place in the American League West.

Part of the reason the A’s acquired Mike Minor in a deal with the Rangers prior to Monday’s Trade Deadline was to fortify a pitching staff that will need as much help as it can get over this upcoming stretch of games. The newcomer will be available to pitch out of the bullpen on Friday night, but Melvin indicated that Minor will get plenty of starts thanks to the impending doubleheaders.

“What looks to be a logjam in the rotation is not,” Melvin said. “We wanted a guy like that, and he’s willing to do anything. He’ll have several starts under his belt just because of the doubleheaders alone.”

As for the rest of the rotation, Melvin plans to keep it in turn. Jesús Luzardo, who was scheduled to start Sunday’s game in Houston before it was postponed, will take the mound on Friday against the Padres. Sean Manaea, Mike Fiers, Chris Bassitt and Frankie Montas will follow.

“We’ll stay in rotation the way we were going,” Melvin said. “We don’t want to back anybody off and give them an even longer time to be inactive. We’ll remain in the five-man rotation where we were, with Minor helping out in the doubleheaders.”

Semien expected to avoid IL

After dealing with soreness in his left side near his rib cage that snapped a streak of 276 games started -- the second-longest streak in Oakland history -- shortstop Marcus Semien took part in infield drills on Wednesday. Although Melvin does not believe Semien will require a stint on the injured list, he does not expect him to play in Friday’s game.

“He’s throwing. Swinging the bat is going to be the biggest issue,” Melvin said. “If I had to handicap it right now, I would say he probably doesn’t play on Friday, and we’ll see where we go from there.”

In the interim, versatile infielders Chad Pinder and Vimael Machín are likely to fill Semien’s spot in a platoon role.