Boston Red Sox ace Chris Sale had Tommy John surgery on his left pitching arm Monday, according to the team.

The procedure was performed by Dr. Neal ElAttrache at the Kerlan-Jobe Institute in Los Angeles.

Sale chose to undergo the procedure now out of fear that delaying it could have caused him to miss significant time in the 2021 season, sources told ESPN's Jeff Passan on March 19.

Recovery from ulnar collateral ligament repairs in the elbow typically takes 12-14 months, putting Sale on pace to return early in 2021. While the coronavirus pandemic-induced delay to the start of the Major League Baseball season was not a direct cause of Sale deciding to undergo the surgery, sources said, the possibility of a significant number of games missed reinforced the decision.

In a conference call earlier this month, Red Sox general manager Chaim Bloom said the surgery "would have happened either way."

Sale, who turned 31 Monday, is entering the first year of a five-year contract worth $145 million he signed last spring. He was shut down with elbow soreness last August after the worst season of his career, during which he went 6-11 with a 4.40 ERA in 25 starts. After an offseason of rest, Sale returned to the mound during spring training but again experienced elbow issues March 1 and was sidelined.

Sale underwent an MRI on March 3, and the results were examined by Red Sox doctors along with renowned surgeons Dr. James Andrews and ElAttrache. Interim manager Ron Roenicke said March 5 that neither Andrews nor ElAttrache recommended surgery for Sale's elbow.

Sale elected to undergo the procedure after having received a platelet-rich plasma injection and gone through other nonsurgical rehabilitation methods that apparently didn't help.

The loss of Sale compounds an offseason of change for the Red Sox, who traded star outfielder Mookie Betts, replaced head of baseball operations Dave Dombrowski with Bloom, parted ways with manager Alex Cora after he was implicated in the Houston Astros sign-stealing scandal and was investigated after accusations of sign-stealing malfeasance during their 2018 championship. MLB hasn't announced its results of that investigation.

Sale, who was traded from the White Sox to Boston before the 2017 season, is 109-73 with a 3.03 ERA in 312 career appearances, including 232 starts. He has struck out 30.7% of batters faced, the highest rate in the live ball era (minimum 1,000 innings pitched). After allowing 17 earned runs over his first four starts last season, he pitched to a 3.83 ERA in his final 21 starts and held opponents to a .207 batting average.

Information from ESPN's Joon Lee was used in this report.