Pruitt has developed inflammation in his right elbow, Brian McTaggart of MLB.com reports.
Houston manager Dusty Baker indicated Tuesday that Pruitt was ailing for an undisclosed reason, so knowing it's an elbow injury clarifies the picture. Pruitt is one of several starters that is expected to serve as depth and was in the mix as a possible replacement for No. 4 starter Jose Urquidy, who was placed on the 10-day injured list for an undisclosed reason.