McCullers (forearm) is expected to throw a bullpen session before Sunday's contest against the Athletics, Danielle Lerner of the Houston Chronicle reports.
McCullers has slowly been working his way back from the forearm injury he suffered in February, and Sunday's session could be his last before launching a rehab assignment. Once healthy, the 29-year-old will be a welcomed addition to Houston's rotation as Luis Garcia (elbow) underwent Tommy John surgery Friday.