Ragans underwent Tommy John surgery Wednesday, T.R. Sullivan of MLB.com reports.
Ragans was diagnosed with a torn UCL in mid-March. He'll now be out until the middle of the 2019 season. The surgery adds a lot of risk to Ragans' profile and costs him significant development time, hurting his value in dynasty leagues. The former first-round pick had a promising 2017 season, recording a 34.8 percent strikeout rate and a 3.61 ERA in 57.1 innings for Low-A Spokane.