NEW YORK — After insisting during a summer slump that he was not ailing, Yankees slugger Aaron Judge had arthroscopic surgery on his left shoulder.

The operation was performed Monday by Dr. Neal ElAttrache in Los Angeles. The Yankees said Tuesday the procedure involved a loose-body removal and cartilage cleanup and Judge should be recovered ahead of spring training.

The 25-year-old Judge hit .284 with 52 homers and 114 RBIs in 155 games this season, helping the Yankees advance to the AL Championship Series, where they lost to the eventual World Series champion Astros. He was a unanimous selection for AL Rookie of the Year and finished second to Houston infielder Jose Altuve in the AL MVP race.

Judge was hitting .329 with 30 homers and 66 RBIs at the All-Star break, then batted .179 with seven homers and 16 RBIs with 67 strikeouts in his next 44 games through the end of August.

He made several crashes into outfield walls and often was seen with packs of ice on his shoulder. While it looked as if an injury might be preventing him from swinging freely, but the right fielder and manager Joe Girardi repeatedly said his shoulder was fine.

He rebounded to bat .311 with 15 homers and 32 RBIs in the final month of the season.