Boxberger (back) is working out daily at Tropicana Field as part of his ongoing rehabilitation, Marc Topkin of the Tampa Bay Times reports.
The veteran reliever resumed a throwing program on April 5, but he isn't expected back before the end of the month. When active, Boxberger is likely to slot in as an eighth-inning option for manager Kevin Cash that can also close out games on days when Alex Colome is unavailable.