NEW YORK -- Matt Allan, who was briefly the Mets’ top pitching prospect before Tommy John surgery derailed the start of his career, has another long rehabilitation in front of him.

The Mets announced Saturday that Allan underwent UCL revision surgery in January. The operation is in effect a second Tommy John procedure with a similar recovery timetable. That means Allan will miss all of the 2023 season, and perhaps some of 2024 as well. Tommy John operations typically require a 12- to 18-month recovery.

It is a significant blow for Allan, a first-round Draft talent whom the Mets were able to select in the third round in 2019 due to signability concerns. Allan did sign and became the organization’s top-rated pitching prospect the following year, earning a late-season promotion and helping push Single-A Brooklyn to the New York-Penn League championship.

But Allan missed a full year of games in 2020 due to the COVID-19 pandemic and never made it back to the mound in 2021. In May, the Mets announced that Allan had torn the ulnar collateral ligament in his right elbow, necessitating Tommy John surgery. During his recovery, Allan fell behind multiple other pitchers in MLB Pipeline’s Mets prospect rankings.

The prognosis for pitchers who undergo multiple UCL procedures is not as strong as for those who have just one, but Allan does have youth working in his favor. Still just 21, Allan could theoretically make it back to game action shortly after his 23rd birthday, giving him time to climb the Minor League ladder at an age when many college prospects are still just beginning their rise.

For now, Allan will begin another rehabilitation program with the aim of throwing in non-game atmospheres this summer. He will be in Minor League spring camp in Port St. Lucie, Fla.