Castano (concussion) recently underwent an MRI that revealed a small labrum tear in his shoulder, Christina De Nicola of MLB.com reports.
Castano has been sidelined with a concussion for over a month, but he resumed mound work in late August. However, his recovery will be delayed due to this shoulder injury. The lefty is expected to rehab the issue rather than undergoing surgery, but it's unlikely Castano will be able to rejoin the Marlins prior to the end of the season.