Perdomo was designated for assignment Saturday, Neil Solondz of the Rays Radio Network reports.
Perdomo was claimed off waivers by the Rays on July 19, but he'll lose his spot on the 40-man roster after Tampa Bay acquired David Peralta from the Diamondbacks on Saturday. Perdomo has struck out 13 in 5.1 scoreless innings over six Triple-A appearances this year and will likely remain in the organization if he goes unclaimed on waivers.