To make room for Lee, the Dodgers optioned pitcher Ian Thomas to Oklahoma City.
Lee, a first-round draft pick of the Dodgers in 2010, is 9-3 with a 2.29 ERA in 14 starts. The Dodgers signed him to a $5.25 million bonus, luring him away from a scholarship opportunity with LSU to be their starting quarterback.
Thomas earned his first win of the year on Friday with a five-inning emergency start in place of Zack Greinke, who was placed on the paternity list. Greinke is expected to start on Sunday.