"I use the one-piece hockey mask," Hayes said. "They used to be really heavy, and about two years they came out with a lighter version. They're not as light as the two-piece like Salvy wears, but I like it because it has better visibility and I feel like it takes a blow a little better. That's why I switched. And it protects you against back swings -- you see guys get hit all the time."
Considering Perez's problems with his mask, the Royals might consider alternative gear for him.
Dick Kaegel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.