Manager A.J. Hinch said McCullers (back) threw a bullpen session at Minute Maid Park on Monday, Jake Kaplan of the Houston Chronicle reports.
McCullers has been playing catch for about a week, but Monday marked the first time he was able to throw off a mound since landing on the disabled list at the end of July. While he's inching closer to a return, he'll still need to progress to facing hitters before eventually being cleared for a minor-league rehab assignment. In the meantime, Brad Peacock will continue to start for Houston.