"It's real black and blue, but of course he lobbied to play today and tomorrow, but I'm like, no, let's be smart about this," Yost said before the game.
Yost said Perez would return to the lineup for Sunday's series finale against Detroit.
Perez bats with a guard on his left shin, but this foul hit above the protective device and got him more in the lower calf.
"He could play, but when it's stiff and it's sore, you just want to make sure you don't strain the calf," Yost said. "So, we'll let him get treatment on it all day today and let some of that inflammation get out of there."
Brett Hayes got his second start at catcher. Perez was available if needed but, if worse came to worse, who would be the emergency catcher? Yost nominated third baseman Mike Moustakas.
"Probably Moose, he caught in high school," Yost said. "We thought Danny [Valencia] might be able to do it, but it's like a near-death experience every time he goes out to warm up a pitcher between innings when Salvy's not ready, so we better re-evaluate that one."
Prior to Saturday's game, Perez was among three Royals to receive their 2013 Gold Glove Awards, along with teammates Eric Hosmer and Alex Gordon.