Boston Red Sox first baseman Triston Casas was placed on the 10-day injured list with a ruptured left patellar tendon Saturday.
Casas left Friday night's game against the visiting Minnesota Twins on a stretcher after suffering the injury in the bottom of the second inning.
He beat out a check-swing tapper that Twins pitcher Joe Ryan misplayed for an error. After stepping hard on top of the first base bag, his left foot hit the foot of Minnesota first baseman Ty France and he fell hard on his left knee.
Red Sox manager Alex Cora called it "a significant knee injury" after Boston' 6-1 win over the Twins.
Cora said Casas didn't fully understand what had happened as he was worked on by trainers.
"It seems like he was in shock, to be honest to you," Cora said. "He said right away that he didn't feel it. It's tough. He works so hard and we want him on the field. That was a hustle play, too, and that happened."
Casas was replaced by Romy Gonzalez at first base.
Casas, 25, is batting .182 with three homers and 11 RBIs in 29 games.
Casas also ran into misfortune last season, when he was limited to 63 games due to a left rib cage injury. He batted .241 with 13 homers and 32 RBIs.
The Red Sox announced several other roster moves Saturday.
Left-handed pitcher Brennan Bernardino was reinstated from the bereavement list.
The Red Sox also activated infielder Abraham Toro from Triple-A Worcester and optioned right-handed pitcher Luis Guerrero to Worcester.
