The Astros and general manager Jeff Luhnow announced the corresponding move to get Brett Oberholtzer on the roster to start on Monday for Houston. Oberholtzer had already been announced as today's starter before the transaction took place.
#Astros manager A.J. Hinch announced Michael Feliz to be sent back to AA tonight in advance of Brett Oberholtzer's return from DL tomorrow.
— #VoteAstros (@astros) May 31, 2015
Feliz, a top five prospect per MLB.com, appeared in one game for the Astros. He struck out one batter, allowed one hit and zero runs.
Brett Oberholtzer has battled a blister issue since Spring Training. He returned to make one start in mid May against the Giants, but eh lasted only three innings. Obe' returned to the DL after that outing and he made one rehab start against the Memphis Redbirds on May 27 - - 4.2 IP, 4 R, 1 ER, 2 HR, 5 K, 0 BB.
So, Feliz was in fact called up to prevent the Astros from cutting someone from the 40-man roster. But the roster issue will continue to be an issue with a backlog of young prospects.