Bender (back) was placed on the 15-day injured list Wednesday, retroactive to May 23, Christina De Nicola of MLB.com reports.
Bender hasn't pitched since May 18, and he's apparently been dealing with a back injury that has kept him out of action. He'll be sidelined until at least early June, while Cole Sulser, Dylan Floro and Anthony Bass should continue to see the majority of high-leverage work in Bender's absence.