PHOENIX -- Jeff Karstens was removed from Tuesday night's game with the D-backs following one inning, suffering from inflammation in his right shoulder.
Karstens will stay with the club, which is returning to Pittsburgh following Wednesday afternoon's game here. Karstens' condition will be evaluated by team doctors in Pittsburgh, with no update expected until Thursday afternoon.
The development with Karstens coincidentally came with A.J. Burnett watching from the Pirates' dugout. Burnett joined the team here following his rehab start with Indianapolis on Monday night, and is due to make one more rehab start (on Saturday in Altoona) before stepping into the big league rotation.
Burnett's arrival could still complicate the Pittsburgh-rotation landscape, forcing out one of the five starters who have been very effective. However, any long-term issues for Karstens would eliminate that problem, albeit not in the desired manner.
Karstens had allowed two runs to the D-backs in the bottom of the first, squandering a 1-0 lead the Pirates had arranged in the top of the inning, but did not visibly appear to be in any discomfort.
After retiring the first two men, he surrendered a double to Chris Young, an RBI single to Miguel Montero, then a run-scoring double to Jason Kubel.
Karstens delivered 20 pitches in that inning, of them 15 strikes.
Jared Hughes took over in the second inning for the Pirates, who scored twice in the top of the third to draw in to a 3-3 tie.
Tom Singer is a reporter for MLB.com and writes an MLBlog Change for a Nickel. He can also be found on Twitter @Tom_Singer. This story was not subject to the approval of Major League Baseball or its clubs.