Motter entered as a pinch runner and scored the game-winning run in Saturday's 4-3 win over Cleveland.
Motter ran for pinch hitter Travis Shaw, who had singled, and eventually came around to score on Alex Verdugo's walkoff single. He joined the Red Sox Saturday as part of the expanded 28-man roster and plays enough positions to help the Red Sox deal with the team's COVID-19 outbreak.