Boxberger (oblique) had a successful 15-pitch bullpen session Thursday, Marc Topkin of the Tampa Bay Times reports.
The 28-year-old closer suffered no setbacks in the brief session, which came on the heels of him playing catch on Monday for the first time since his latest injury. Already on his second DL stint in 2016, the veteran pitcher was cautiously optimistic following the latest development. "Everything was feeling well," Boxberger said. "I'll progress from there."