De Leon, Tampa Bay's No. 3 prospect and No. 28 overall as ranked by MLBPipeline.com, made his Major League debut for the Dodgers in 2016, going 2-0 with a 6.35 ERA. He was traded to the Rays for infielder Logan Forsythe during the offseason.
The right-hander went 1-0 with a 2.16 ERA in two starts for Class A Advanced Charlotte before being promoted to Triple-A Durham, where he allowed four earned runs in four innings in his only start for the Bulls.
De Leon, 24, was drafted by the Dodgers in the 24th round in 2013.