Naylor was scratched from Friday's lineup against the Mets due to an illness, Tim Booth of The Seattle Times reports.
There's been a bug going around the Mariners' clubhouse, and Naylor is the latest to catch it, per Shannon Drayer of SeattleSports.com. Naylor will rest Friday but could be back for Saturday's matinee if he's recovered enough. Mitch Garver will serve as the Guardians' designated hitter in Naylor's absence.