The Houston Astros pitcher was taken off the field on a stretcher after he fell trying to cover first base.
The Astros said that they will release more information when available.
The pitcher, who entered the game with a 15 1/3 strikeout streak, appeared to twist his left leg awkwardly on the delivery to Kike. When he turned to cover first base, he took a step and then fell down on the grass.
Astros staff rushed to tend to him after the out was recorded. He was loaded onto a stretcher and taken to an exit. Astros teammates hovered around the infield as a stretcher arrived.
The veteran entered the game with a 3-2 record and a 3.38 earned run average, along with 17 strikeouts. He left the Red Sox with a 2-1 lead. The game was delayed by rain and was tied at 2-2.
The report was contributed to by the Associated Press.