Houston placed Urquidy on the 15-day injured list Monday with right shoulder discomfort.
The Astros haven't revealed the results of the MRI that Urquidy underwent after he exited his start in Sunday's win over the Phillies after throwing 83 pitches, but the team apparently wasn't convinced that the right-hander would make a full recovery from the shoulder issue in advance of his next turn through the rotation. Thanks to an off day Thursday, the Astros will be able to get by with a four-man rotation until May 9. Right-hander Brandon Bielak was called up from Triple-A Sugar Land in a corresponding move and should be able to cover multiple innings out of the bullpen.