McCullers (forearm) will get an MRI on Friday after reporting discomfort, Julia Morales of AT&T SportsNet Southwest reports.
McCullers had been on target for a mid-July return before being shut down from throwing off a mound in late May. His new timetable remains unclear, but the Astros are hoping to have a better idea once the imaging results come in early next week. The 29-year-old righty has been shelved all season with a right forearm stain.