Motter was designated for assignment by the Red Sox on Tuesday, Christopher Smith of The Springfield Republican reports.
Motter filled in for the Red Sox amid the team's current COVID-19 outbreak, but he'll be cast off the 40-man roster after Danny Santana (undisclosed) and Enrique Hernandez (illness) were reinstated from the COVID-19 injured list. He went 2-for-6 with a triple, a double, three runs and an RBI across three appearances with the Red Sox.