Griffin will report to the Pirates' facility in Bradenton on Sunday to continue rehabbing his right forearm strain, Aidan Stepansky of MLB.com reports.
Griffin began playing catch out to 90 feet Wednesday and is expected to gradually increase the distance and intensity of his throwing while he's in Florida. The standout rookie has been on the shelf since May 31 but could return to action before the end of June, depending on how quickly he's able to resume full baseball activities.