Oakland starter Brandon McCarthy is done for the evening after taking a line drive off of the right knee in the fourth inning.
McCarthy, who recovered from a six-run Rangers second with a 1-2-3 third, had one out when Endy Chavez drilled a line drive up the middle that appeared to strike the starter around his right knee.
The ball ricocheted to the vast first-base foul territory at O.co Coliseum, and Chavez advanced to second.
McCarthy was down for a few minutes in obvious pain before walking off his limp and leaving the game. Reliever Trystan Magnuson took his place on the mound.
Ian Kinsler would bring Chavez home with a single to center for a 7-0 Rangers lead. Two batters later, Michael Young brought Kinsler and Elvis Andrus home with a single, and the Rangers have a 9-0 lead in the fourth.