OAKLAND -- The A’s could add another big arm at some point during their current eight-game homestand.

A.J. Puk is nearing the end of his rehab from a left shoulder strain. After throwing to hitters at the A’s alternate training site in San Jose on Friday, the left-hander is scheduled for another session on Sunday. After that, his next appearance could come in the big leagues.

“I don’t know that there’s time to get him stretched out as a starter,” A’s general manager David Forst said before the A’s returned to action Friday night vs. the Padres. “I think we’re still looking at him as a reliever, albeit one who can throw more than an inning at a time. He’ll be valuable in that role. We look towards activating him next week.”

Puk, ranked by MLB Pipeline as Oakland’s No. 3 prospect, pitched well out of the A’s bullpen last season. He posted a 3.18 ERA in 10 relief appearances and struck out 13 batters over 11 1/3 innings.

The A’s could use his electric arm in a stretch that will see them play four doubleheaders over the final 20 days of the regular season. A positive COVID-19 test forced the postponement of four scheduled games this week.

Semien feeling better
Shortstop Marcus Semien hit off a tee in the batting cage on Friday afternoon and was optimistic about returning at some point during this homestand. This development is a positive, as A’s manager Bob Melvin was expecting Semien to require more time before getting a bat back in his hands.

Semien felt soreness near his left rib cage after the first game of a doubleheader last Saturday in Houston, leading to him being scratched from the lineup for the second game to snap a streak of 276 consecutive games started, the second-longest streak in Oakland history.

“I’ve been doing a lot of work in the weight room and training room. This was the first day hitting back in the cage off the tee,” Semien said. “I won’t be hitting [batting practice] on the field today, so I doubt I get an at-bat. I’m going to prepare like I’m available off the bench to do whatever they ask.

“Hopefully, during this time [the injury] gets better and my confidence gets better as I work in the cage. Everything we did with the MRI and CT scan looked pretty good, it’s just a matter of working out the inflammation and seeing what I can manage.”

Vimael Machín got the start at short on Friday night in place of Semien. Machín is expected to get the bulk of playing time at the position against right-handed pitchers while Semien is out, with Chad Pinder playing there against left-handers.