McCullers (back) was officially activated from the disabled list to start Saturday's game against the Mariners, Brian McTaggart of MLB.com reports.
McCullers was confirmed as Saturday's starter earlier in the week, but now the corresponding moves have been clarified. Upon McCullers' return, the club optioned Joe Musgrove to the minors and also placed Brad Peacock on the paternity list. The 23-year-old was sharp on the mound prior to being placed on the disabled list and will look to continue that in his first start back Saturday.