Ruiz (head) was taken to a local hospital for a CT scan after leaving Monday's game against the Padres, Mark Zuckerman of MASNSports.com reports.
Ruiz was struck by a foul ball while in the dugout and sent for further evaluation after a lump formed on the left side of his head, per Zuckerman. Riley Adams would be in line for more chances behind the plate if Ruiz is forced to miss time.