Grimm was optioned to Triple-A Iowa on Saturday, Bruce Levine of 670 The Score reports.

EDGE Analysis

Grimm hasn't allowed a run in his last 10 appearances, but the Cubs needed to free up a roster spot for Brian Matusz, who will be added to the 25-man squad to start Sunday's matchup with the Mariners. The right-handed Grimm struggled through May and June but has notched seven strikeouts while allowing just two hits in 6.1 July innings.