Contreras was removed from Saturday's game against the Diamondbacks due to right hamstring tightness, Patrick Mooney of The Athletic reports.
Contreras started Saturday's game as the designated hitter and went 1-for-2 with a stolen base. While he singled and swiped a bag in the bottom of the third inning, he apparently tweaked something since Rafael Ortega took over as a pinch runner. The severity of the 30-year-old's injury isn't yet clear, but Yan Gomes should see increased work behind the dish if Contreras misses additional time.