Moustakas has been dealing with a tight hamstring since Wednesday, when he was scratched from the lineup against Red Sox lefty Jon Lester. The hamstring and Saturday's left-handed starter were the two reasons manager Ned Yost said he opted to sit Moustakas on Saturday.
"He got through the game pretty good [Friday] night, didn't hurt it any further than it was. He's about 85 percent," Yost said. "[With a] lefty going, it's a good day to give him a break."
Yost said he told Moustakas on Friday night that he wouldn't start at third base, noting Saturday's wet and slippery conditions weren't a factor in giving the third baseman the day off.
Irving Falu started at third base and batted seventh on Saturday.