The Rays optioned Pruitt to Triple-A Durham on Friday.
Pruitt has been solid over his last eight outings (33 innings) with a 3.27 ERA, 1.03 WHIP and 21:4 K:BB, but he heads to the Bulls to make room for the return of Daniel Robertson (hamstring) from the disabled list. Pruitt allowed six runs on 10 hits over eight innings with Durham earlier this season.