Gossett debut Wednesday

ST. PETERSBURG, Fla. — The A’s made it official Sunday morning: Right-hander Daniel

Gossett will make his bigleague debut Wednesday at Miami.

Gossett, 24, was the A’s second-round pick in the 2014 draft after pitching at Clemson. He’s 3-3 with a 3.56 ERA at Triple-A Nashville and has allowed only four runs over his past three starts.

“You’d like to get a guy here for his debut when he’s pitching well, and he is,” manager

Bob Melvin said. “The timing is good for that.”

Gossett will be working on eight days of rest, so he was scheduled to have a “significant” side session Sunday, according to Melvin.

The A’s saw Gossett during the spring as a nonroster invitee; he pitched in three games and gave up only two hits, holding opponents to a .100 average, but he walked six in 61⁄3 innings and allowed three runs in his first big-league camp.

“He’s got a quick arm. There’s some deception. He’s got a really good cutter, a good changeup — a good mix of pitches,” Melvin said. “And he’s got some good presence on the mound, too.”

Gossett will be starting after

Andrew Triggs was placed on the disabled list Saturday with a left hip strain. Triggs is expected to miss only a start or two.

The A’s will need to make a 40-man roster move to add Gossett. Reliever Ryan Dull, out since May 20 with a knee injury and still unable to throw off the mound, is a candidate for the 60-day DL.

As expected, Oakland demoted reliever Frankie Montas on Sunday to drop to 25 players after adding a 26th man for Saturday’s doubleheader. Montas had a 6.91 ERA and has allowed 15 walks and nine homers in 282⁄3 innings.

“He’s going to be a monster in this league, I believe that,” Melvin said. “He just wasn’t able to get out of a little bit of a rut . ... He’s got a terrific skill set, and he’s going to be really good.”

Melvin said Montas needs to work on his secondary pitches and learn not to overthrow when pitching just one inning.