Howard cleared waivers and was outrighted to Triple-A Toledo on Saturday.
The Tigers designated Howard for assignment Tuesday.
Howard was claimed off waivers by the Tigers on Friday.
Howard was designated for assignment by the Pirates on Saturday.
The Pirates optioned Howard to Triple-A Indianapolis on Monday.
The Pirates recalled Howard from Triple-A Indianapolis on Tuesday.
The Pirates activated Howard (back) from the 10-day injured list Wednesday and optioned him to Triple-A Indianapolis, Jason Mackey of the Pittsburgh Post-Gazette reports.
The Pirates shifted Howard's (back) rehab assignment from Low-A Bradenton to Triple-A Indianapolis on Tuesday, Jason Mackey of the Pittsburgh Post-Gazette reports.
Howard (back) will begin a rehab assignment at Low-A Bradenton on Friday, Alex Stumpf of DKPittsburghSports.com reports.
The Pirates placed Howard on the 10-day injured list Tuesday with a mid-back strain, Justice delos Santos of MLB.com reports.