Grace was optioned to Triple-A Syracuse on Friday, Dan Kolko of MASN Sports reports.
The 28-year-old southpaw saw mixed results in his first stint with the big league club this season, but with Shawn Kelley and Koda Glover returning from injuries in time for Friday's game with the Phillies, Grace's services were no longer needed. He'll return to the Triple-A bullpen where he'll look to improve on the middling 4.91 ERA he currently possesses with the Chiefs.