The Kansas City Royals will be without Alex Rios and Kelvin Herrera for a period of time after the pair were diagnosed with chicken pox.

There is concern that other members of the club may contract chicken pox, which could cause the American League Central leaders to stumble. Rios and Herrera likely will miss a couple weeks after both were sent home from Tampa Bay over the weekend.

"Think there is always a concern because these guys were in for three or four days before they showed signs of it," Ned Yost said. "Since that point, (trainer) Nick Kenney has done a real good job of monitoring."

The Royals have reached out to players, coaches and family members to determine whether they have had chicken pox or been vaccinated. Most of them should be in the clear, but Yordano Ventura acknowledged that he has never had the virus, and several others from Latin America -- where vaccinations happen less frequently -- also may be at risk.