BOSTON -- Jasson Domínguez is set to undergo Tommy John surgery on Sept. 20 to repair a torn ulnar collateral ligament, Yankees manager Aaron Boone said on Thursday at Fenway Park.

Domínguez’s estimated return to big league play is 9-10 months, according to Boone. Dr. Keith Meister will perform the procedure. While it is possible that the surgery could involve an internal brace, the Yankees said that would not change the team's timetable for Domínguez's return. 

“We’re excited about the player we think he’s going to be,” Boone said. “There’s still a lot of development to be had there. First thing's first is getting through this and hopefully going through a really good winter of rehab.”

Domínguez is rated the Yankees’ No. 2 prospect and the No. 74 prospect in all of baseball, according to MLB Pipeline.

Boone said the Yankees hope Domínguez will be close to resuming baseball activities, including swinging a bat, when he reports to Spring Training in February.

According to Boone and Domínguez, the injury can be traced to his third game in the Majors, a Sept. 3 contest against the Astros in Houston. Domínguez said he “felt like something wasn’t right” pregame, but he could still play, hitting his second big league homer in a Yankees win.

After an off-day, Domínguez said he was able to loosen up enough to play in his Yankee Stadium debut on Sept. 5, first reporting the discomfort to the team’s training staff on Sept. 6 -- another game in which he homered.

Domínguez said that he was receiving treatment, but the discomfort had “gotten progressively worse.” He was scratched from Sunday’s series finale against the Brewers after feeling unable to swing the bat with authority.

The Yankees rattled off a five-game winning streak after Domínguez and catcher Austin Wells were promoted as September callups. Domínguez became the youngest player in the Modern Era (since 1900) to homer in four of his first seven AL/NL games.

The switch-hitting center fielder slashed .258/.303/.677 (8-for-31) with six runs, one double, four homers, seven RBIs, two walks and one stolen base in eight games.

“It was a really good experience,” Domínguez said. “I was fortunate to be here, to be able to play those eight games and really see how it is inside this clubhouse in the big leagues.”