Span said he didn't feel well all game, but felt it the worst while chasing Lorenzo Cain's double to center field in the seventh.
"I was a little dizzy," Span said. "I wasn't feeling great a majority of the game. The inning before I chased Cain's ball and when I looked up I could feel my head spinning a little bit. I felt like I was moving in slow motion, so I felt it was best if I came out of the game."
Span, who dealt with dizziness last season after suffering a home-plate collision in early June, said he's hopeful that he'll be ready for Sunday's rubber game at Kauffman Stadium.
"This is probably the worst I've felt all year, but I'm going to go to sleep and hopefully I'll feel better [Sunday]," Span said. "I'm not too worried about it."
Span was replaced in center field by Ben Revere, who moved over from right. Darin Mastroianni entered to replace Revere in right.