Oliveros was scheduled to have bone chips removed from his elbow but doctors found ligament damage as well, so ligament replacement surgery was performed. Oliveros, who is expected to be out approximately 12 months, was aware of the possibility, according to Antony.
"They did the clean up and when they checked the gap they determined he needed Tommy John," Antony said. "He also had some large loose bodies in there removed that were causing irritation."
Oliveros, 24, was acquired from the Tigers in the trade that sent Delmon Young to Detroit last season. The hard-throwing right-hander posted a 2.42 ERA with 51 strikeouts in 48 1/3 innings between Double-A New Britain and Triple-A Rochester this season. He also made one appearance with the Twins, allowing one run over 1 2/3 innings.