Pelchy, who signed with Tampa Bay as a non-drafted free agent out of Virginia Commonwealth University in June, went 0-2 with a 5.25 ERA in 12 appearances out of the bullpen for the Rays' Gulf Coast League affiliate in his first pro season.
Tampa Bay released the right-hander after the season. His suspension will begin when when he signs with a new organization.
Pelchy's suspension came two days after outfielder Cody Rogers -- another Rays prospect -- was hit with identical sanctions for similarly refusing to take a drug test. In all, six players who spent this season in the Tampa Bay system have been suspended for violating the league's drug program in 2012.