Mets top pitching prospect Zack Wheeler, who is expected to be in the starting rotation at some point this season, suffered a setback on Tuesday.

Wheeler, who is in Triple A with the Las Vegas 51s, will miss his next scheduled start and will fly to New York to undergo an MRI exam on his collarbone after dealing with a sore clavicle. After a poor start to the season, he has turned it around winning two games and allowing three runs in his past three starts. The Mets had hoped he would be in the starting rotation by mid-June, but this recent setback could push back that timetable.

Drafted sixth overall by the Giants in 2009, Wheeler was traded to the Mets in 2012 as part of the Carlos Beltran deal. He is 2-1 with a 3.74 ERA and 47 strikeouts in eight starts.