The A's may play it safe with Crisp and hold him out of action through Thursday's off-day in advance of a nine-game road trip through Cleveland, Tampa and Toronto.
He's most bothered by the injury when turning his head hitting left-handed.
"It really is a day-to-day proposition," said manager Bob Melvin, "and this is one I don't have a lot of experience with, as far as that whiplash thing."
In Crisp's place, Craig Gentry has started each of the last five games in center field and entered the day 3-for-13 in his last four.
Jane Lee is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.