BOSTON — Red Sox chief baseball officer Craig Breslow confirmed what had been assumed Saturday: first baseman Triston Casas will miss the rest of the season after suffering a serious knee injury Friday night.

Casas suffered the injury when he hit first base awkwardly trying to beat out an infield single in the second inning. He hit the bag and immediately crumbled to the ground, grabbing his left knee. Casas had to be carted off the field. Here's the play:

Triston Casas suffered a serious knee injury after a collision at first base in the second inning during Friday’s game against the Twins.