De Leon was recalled from Triple-A Durham on Saturday, Marc Topkin of the Tampa Bay Times reports.
The 27-year-old righty has a 3.51 ERA, 1.32 WHIP and 73:27 K:BB in 51.1 innings at Triple-A, working primarily as a starter. He has a 6.35 ERA in 22.2 innings in his big-league career. Look for him to work as a multi-inning reliever.