The book on Perez, the Royals' top catching prospect after Wil Myers was switched to the outfield, was that he's probably two years away from the Major Leagues.
"I think he's real close to being ready to catch in the big leagues right now," Yost said.
OK, that's not a very likely development immediately, even though Yost on Tuesday declared the catching spot "wide open" in the absence of veteran Jason Kendall, who is recovering from shoulder surgery.
The other three catchers on the 40-man roster are the largely untested Brayan Pena, Lucas May and Manny Pina. Perez, who has not played above Class A, is in his first Major League camp.
So Perez is likely to start the season at Double-A Northwest Arkansas. But, if the Royals were to get in a midseason pinch for a catcher, might Yost put out a call for Perez?
"I wouldn't hesitate for a second," Yost said.
Yost likes Perez's quick, strong arm, the way he blocks the ball and his leadership qualities. His drawback has been offense but he made good progress last year.
"There's a lot going on with that kid -- all positive," Yost said.
But don't look for him on the Opening Day roster in Kansas City.
"I mean I don't see Salvador Perez making the big league team, but he's getting closer," Yost said.