Four months after he reinjured his elbow in spring training, Phillies reliever Seranthony Dominguez had surgery Thursday.

Dominguez underwent a reconstruction of the ulnar collateral ligament in his right elbow, commonly known as Tommy John surgery, the team announced. Prominent orthopedic surgeon James Andrews performed the surgery.

The Phillies weren't expecting Dominguez to pitch during this pandemic-shortened, 60-game season. By not having the surgery until now, he likely won't be ready to return to the mound until the latter part of next summer.

Dominguez initially delayed getting a second opinion — and ultimately having surgery, despite a recommendation that he would need it — to go home to the Dominican Republic in March before travel restrictions were imposed due to the coronavirus. He returned last month but could not have the surgery until now.

Asked last week about Dominguez's status, Phillies general manager Matt Klentak said, "The reason that [the surgery] has been further delayed is a reason that I can't really talk about. He's doing fine. He's healthy. He's preparing for that surgery."

Dominguez’s elbow problems trace back nearly 14 months. He left a June 5, 2019, game against the San Diego Padres because of pain in his right elbow/forearm and missed the rest of last season. He got two medical opinions, including Andrews', both of which suggested rest and rehabilitation rather than surgery.

The Phillies were optimistic about Dominguez's health in spring training. He appeared in two Grapefruit League games before reporting a return of the discomfort in his elbow after a March 8 game against the Toronto Blue Jays.

Dominguez figured to be a key member of the bullpen this season. He burst onto the scene as a rookie in 2018, posting a 2.95 ERA and 74 strikeouts in 58 innings over 53 appearances. But his velocity decreased last season en route to a 4.01 ERA and 29 strikeouts in 24 2/3 innings before getting hurt.

Extra bases

The Phillies added left-hander Cristopher Sanchez to the player pool and assigned him to their alternate training site at Lehigh Valley.

Sanchez is the fifth player added since the start of the season, joining infielders Bryson Stott and Nick Maton, utility man Austin Listi, and right-hander Adonis Medina.