Cain said he felt a twinge in his hamstring while making his last pitch to Justin Turner, whose fly ball to left field ended the sixth inning. The right-hander began warming up to pitch the seventh inning and protect San Francisco's 1-0 edge. However, having endured two stints on the disabled list last season with right hamstring injuries, Cain refused to risk a recurrence.
"It just kind of bit on me a little bit," said Cain, who was replaced by left-hander Steven Okert. "It was something I was kind of monitoring in between the inning and I went back out there. ... I didn't want to go down that road again. With the history of it, I didn't want to push it."
Cain also took Yasmani Grandal's fourth-inning smash off his right foot, with the ball caroming to third baseman Christian Arroyo, who threw out Grandal. After that play, a member of the Giants' athletic training staff briefly checked on Cain, who unhesitatingly stayed in the game. X-rays taken on his foot came back negative.