Kempner was optioned to Triple-A Jacksonville on Tuesday.
The right-hander fired 2.1 scoreless innings Monday against the Phillies and is being sent down Tuesday in favor of a fresh bullpen arm (Dax Fulton). Kempner has given up just three hits with a 10:2 K:BB across nine scoreless frames in the majors this season, so it should only be a matter of time before he gets another look with the big club.