Boston Red Sox left-hander Rich Hill was placed on the 15-day injured list on Saturday, one day after leaving his start against the Chicago Cubs with a sprained left knee.
Right-handed pitcher Phillips Valdez was called up from Triple-A Worcester to fill Hill's spot.
Hill had a 4-0 lead through four innings Friday before exiting during a three-run fifth inning. He said he felt a "pop" in the knee on a breaking ball in the fifth and in the moment thought it was something he could pitch through.
Hill appeared to be shaking his left leg at one point in the fifth and was visited by an athletic trainer.