Philip Humber, who pitched a perfect game for the Chicago White Sox last year, was designated for assignment by the Houston Astros on Sunday.
He gave up five runs while only getting two outs in a loss to the Texas Rangers on Saturday and has struggled all season.
Humber was 0-8 with a 9.59 ERA before being taken off the 25-man roster.
He started the season in the rotation, but was moved to the bullpen on Wednesday. He threw 1 1/3 scoreless innings in relief on Thursday before taking the loss in his second relief appearance on Saturday night.
On April 21, 2012, Humber became the 21st player in Major League history to pitch a perfect game.
Houston signed right-hander Edgar Gonzalez to take his spot on the roster