Peters (back) was transferred to the 60-day injured list Thursday, Mike Persak of the Pittsburgh Post-Gazette reports.
Peters was already ruled out for the season after landing on the 10-day IL late last week, and the move to the 60-day IL is just a procedural move to free up a spot on the 40-man roster. The 29-year-old recently resumed throwing and should have plenty of time to build back to full strength for spring training.