A’s beat: Montas’ back tightness forces him to miss start.

The A’s scratched scheduled starter Frankie Montas with back tightness before Friday night’s game against the Giants, but manager Bob Melvin said the hope is that Montas will still pitch in the series.

Rookie lefthander Jesús Luzardo started against the Giants on Friday. Luzardo had been scheduled to go Saturday afternoon, with Sean Manaea pitching Sunday.

Melvin said that if Montas, who began to feel some upperback discomfort Thursday, can’t go Saturday, Manaea will start the second game of the series. Every starter will just move up one slot until Montas returns.

Montas, the A’s Opening Night starter, is 21 with a 1.57 ERA and 22 strikeouts in 23 innings; the team did not provide specifics about the injury or how much time he might miss, but the fact he was not placed on the injured list indicates they believe he could be on the mound soon.

Luzardo did not get much training camp time because of a positive coronavirus test and he opened the season in the bullpen to build up his innings. Before Friday, he had appeared in four games and made two starts, going 10 with a 2.60 ERA overall.

The A’s are coming off a day off, so they should have a wellrested bullpen for the threegame series at San Francisco. “We have guys who can pitch multiple innings,” closer Liam Hendriks said, suggesting former Giant Burch Smith might be a good option to go long if needed. “We have enough guys who can absorb innings.”

Weems off IL: Reliever Jordan Weems, who missed two weeks with a lat strain, came off the injured list and was optioned to the A’s alternate site in San Jose.

Weems, a nonroster player during the spring and July training camp, made his bigleague debut July 28 against the Rockies, and in two outings, he had a 3.60 ERA and .278 opponents average.

Melvin said that Daniel Mengden has provided good work in a longman role, which might be more what the A’s need for the time being, but that he anticipates Weems will be back at some point.