De Leon was sent down to Triple-A Durham after making his season debut Monday night, Marc Topkin of the Tampa Bay Times reports.
De Leon was called up to give the Rays some bullpen reinforcements after Sunday's game required them to use seven relievers. He earned the win Monday night, but that was despite allowing three runs on four hits over just 2.2 innings. With the Rays' bullpen still in rough condition after six pitchers worked Monday night, expect another fresh arm to come up from Durham in De Leon's place.