De Leon was recalled from Triple-A Durham on Wednesday, Juan Toribio of MLB.com reports.
De Leon will provide an extra bullpen arm for Wednesday's game against the Red Sox after the Rays traded away a trio of relievers earlier in the day. He's spent most of the season with Durham, compiling a 3.43 ERA, 1.48 WHIP and 58:23 K:BB in 39.1 innings.