Detwiler was placed on the 15-day injured list with low back pain Saturday, retroactive to July 8.
Detwiler has been relatively effective since the start of July, posting a 2.25 ERA and 1.25 WHIP in four innings over four relief appearances. However, he's dealing with a back issue that will keep him sidelined until at least July 23. Right-hander Buck Farmer's contract was selected from Triple-A Louisville to take his place in the rotation.