De Leon will be promoted from Triple-A Durham on Monday to serve as a reliever in the Rays' series opener with the Rangers, Marc Topkin of the Tampa Bay Times reports.
The Rays will still hand Monday's start to Erasmo Ramirez, who came on in relief during Sunday's 15-inning win over the Twins to record a 12-pitch save. Ramirez's workload will likely still be monitored carefully Monday, so it wouldn't be surprising if De Leon, who last pitched for Durham on May 23, piggybacked him during the outing and covered multiple innings out of the bullpen. The Rays don't have an opening in their rotation, so it's possible that De Leon will be sent back to Durham in the coming days once the team's other relievers have sufficiently recovered from Sunday's marathon.