Wimmers, who was diagnosed with an ulnar collateral ligament strain earlier this season, suffered a setback in his first start in the Gulf Coast League on July 23. He recorded just two outs before complaining of pain in his elbow.
He flew to the Twin Cities earlier this week and had an MRI on his elbow that revealed a torn UCL and the decision was made to have ligament-replacement surgery on Thursday. He's expected to be out approximately 12 months.
"He had an MRI and it revealed that there was a change and that he needed to have it," Antony said of the surgical procedure. "They figured he had to have it, he stayed in town, did what they needed to do on Wednesday and is having it this afternoon."
Wimmers, rated as Minnesota's No. 12 prospect heading into the season according to MLB.com, is the second-best pitching prospect for the Twins to undergo Tommy John surgery in the last year.
Right-hander Kyle Gibson had the same surgery last September, but is on the comeback trail, as he's as he's made seven appearances in the Gulf Coast League. Gibson, ranked as the club's sixth overall prospect according to MLB.com, has a 2.61 ERA with 11 strikeouts and three walks in 10 1/3 innings.
Antony said he saw Gibson pitch in Florida and that he looked better than ever, and indicated he could move up to Class A Fort Myers to continue his rehab soon.
"Since we drafted him, that's as good as I've seen him throw the ball," Antony said. "More velocity than I saw when he was at Rochester and before that, because he was consistently 93-94 [mph], and his slider was 84-86 [mph] with good life."