Eovaldi had a torn flexor tendon and partially torn ulnar collateral ligament. It was the second Tommy John surgery for the 26-year-old, who had the procedure nine years ago when he was a high school junior.
He is expected to miss the remainder of this season and all of next year. It's a stunning setback for the Yankees, who hoped Eovaldi would be a key cog in their rotation for several seasons when they acquired him from the Miami Marlins in December 2014.
One of the hardest-throwing starters in the majors, Eovaldi was 9-8 with a 4.76 ERA in 124 2/3 innings this year. He can become a free agent after next season.