Minnesota Twins right-hander Boof Bonser will have exploratory arthroscopic surgery on his ailing shoulder, which has kept him off the mound since the start of spring training. 

Bonser was experiencing persistent soreness in the joint and sought a second opinion. Manager Ron Gardenhire says the doctor's recommendation after the latest MRI exam was to "go in there and clean up." 

There won't be a timetable for Bonser's recovery until the results of the surgery are assessed. 

After getting bumped from the rotation last year, Bonser struggled in the bullpen for most of the summer before getting back on track in August. His ERA was 5.93 in 118-plus innings, but the hard-throwing Bonser was in line for a long role in relief.