Davis, 24, began this season in the big league rotation but struggled and was sent to Triple-A Louisville. Over two big league stints, he was 1-3 with an 8.63 ERA in seven games, including six starts. He had a 4.77 ERA in 11 starts for Louisville, and missed time on that club's disabled list with a back injury.
The Reds shut Davis down following a poor start vs. the Cardinals on Sept. 20.
Ranked the No. 19 prospect in the organization by MLBPipeline.com, Davis was one of four players acquired in the December 2015 trade that sent closer Aroldis Chapman to the Yankees.
It is not yet clear when Davis can begin baseball activities to get ready for next season. Before he was injured, the Reds had hoped he could be a factor to compete for a spot in either the big league rotation or bullpen.
Mark Sheldon has covered the Reds for MLB.com since 2006, and previously covered the Twins from 2001-05. Follow him on Twitter @m_sheldon and Facebook and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.