Butler, 24, allowed six runs in four innings in the Rockies' 12-3 loss to the New York Mets on Thursday, dropping to 3-10 with a 5.90 ERA this season. He has walked 42 and struck out 44 in 16 starts over two stints with Colorado.
Colorado might soon receive a boost to its starting rotation. David Hale could start Tuesday after being sidelined since July 10 with a strained left groin.
Logan was shut down late last August with elbow inflammation. He's 0-2 with a 4.75 ERA this year.