De Leon was recalled from Triple-A Durham on Monday, Bill Chastain of MLB.com reports.
As was initially reported by Buster Olney of ESPN earlier in the day, De Leon will join the big club for the first time this season, providing the Rays with a fresh arm out of the bullpen after Tampa Bay used seven relievers -- including Monday's starter, Erasmo Ramirez -- in Sunday's 15-inning victory over the Twins. Ramirez only needed 12 pitches to record the save Sunday, but it wouldn't be surprising if Rays manager Kevin Cash monitored the right-hander's workload carefully in his second appearance in as many days. If that's the case, De Leon could be asked to cover multiple innings in relief Monday in what would be his Rays debut.