Peacock was sent home by the team on Tuesday, in hopes of minimizing the exposure to teammates.
The contagious illness is common among small children, but still possible in adults.
Doctors say the illness can cause sores, sometimes painful, in or on the mouth and on the hands and feet. The illness usually doesn't last more than a week or so.
Peacock is 2-4 on the season with a 2.98 ERA and three saves. He'll be available to pitch Friday night against the Arizona Diamondbacks.
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