McCullers (back) played catch in Houston on Monday, Jake Kaplan of the Houston Chronicle reports.
This is an encouraging development, as it was the first time McCullers has thrown since landing on the disabled list at the end of July. Still, the 23-year-old remains without a timetable for his return, and the Astros will likely continue to proceed cautiously with him given his injury history. Brad Peacock will continue to fill in for him in the rotation while he's sidelined.