Contreras started at first base and went 2-for-3 with a walk and a run scored in Sunday's 4-1 win over Kansas City.
Contreras was activated off the injured list Sunday, and the Red Sox felt confident using him in the field. In addition to scoring Boston's final run, Contreras showed the hamstring wasn't an issue in the fourth inning, when he reached base on a throwing error and advanced to second.