Bostick, 23, spent the year between playing in Double-A and Triple-A for Washington where he had a .700 OPS and eight homers in 135 games. He was acquired by the Nationals in December 2014, along with right-hander Abel De Los Santos in exchange for left-hander Ross Detwiler.
Jamal Collier covers the Nationals for MLB.com. Follow him on Twitter at @jamalcollier. This story was not subject to the approval of Major League Baseball or its clubs.