TAMPA — Frankie Montas, who underwent shoulder surgery Tuesday, is expected to be sidelined at least until August, but the Yankees are leaving the door open for a late-season return.

Montas had his labrum “cleaned up” during the procedure, according to manager Aaron Boone, but Dr. Neal ElAttrache, who performed the surgery, did not have to touch the right-hander’s rotator cuff.

The result is that Montas will be shut down for 12 weeks before his rehab schedule will have him begin a throwing program in May. Generally the shutdown time is equal to the time needed for a ramp-up, meaning that Montas would need 12 more weeks to be built up — putting his potential return some time in August, in a best-case scenario.

“We’re hopeful that, at some point, he can get back,” Boone said Wednesday. “But I don’t want to best-case/worst-case. It’s starting the rehab process now. Right now, the protocol, if everything goes right, suggests 12 weeks [down] and then we start ramping up.”

Montas, who was on the injured list with shoulder inflammation shortly before the Yankees acquired him from the Athletics at the trade deadline last year, is set to be a free-agent after this season.

In Montas’ absence, Domingo German and Clarke Schmidt are set to battle for the fifth starter job in spring training.

Catcher Ben Rortvedt also underwent a shoulder procedure Wednesday, but his was for “an aneurysm of his posterior artery near his left shoulder,” according to Boone. Rortvedt was having a circulation problem in his finger and went to see specialists, who revealed the diagnosis. Rortvedt will be shut down from baseball activities for a month, meaning he will start the season late at Triple-A Scranton/Wilkes-Barre.

Last year, Rortvedt also had his season delayed by an oblique injury before later needing knee surgery.

The Yankees brought in a Triple-A umpire for live batting practice to call balls and strikes and enforce the pitch clock. The only two apparent violations were one on Carlos Rodon and one on DJ LeMahieu.

“I thought [it went] really well,” Boone said. “I feel like these first few days, from that standpoint, has been a success.”

Nestor Cortes is set to face hitters Thursday for the first time this spring after having his ramp-up briefly delayed by a hamstring strain. … After he threw two simulated innings on Thursday, Gerrit Cole will face hitters again his next time through before getting into Grapefruit League action. … Schmidt will start the Yankees’ Grapefruit League home opener on Sunday against the Braves.