Santana was optioned to Triple-A Oklahoma City on Sunday, Ken Gurnick of MLB.com reports.
Santana was the first reliever used after starter Caleb Ferguson on Sunday for the Dodgers' bullpen day, but he allowed three runs on three hits and three walks. The 23-year-old had severe issues with his control as he also had a wild pitch and hit a batter, though he did manage four strikeouts. Josh Sborz was called up from Oklahoma City in a corresponding move to provide a fresh arm for the bullpen.