Span exited the game in the eighth inning, with a health problem that Twins manager Ron Gardenhire said was related to the heat.
The game time temperature was 99 degrees and the Twins were wearing throwback jerseys that were bigger and thicker than their regular uniform tops.
"He just felt a little lightheaded, which is expected in this heat," Gardenhire said. "It could happen today. It's one of the reasons I'm catching Drew [Butera]. Let the youngest buck catch out there. Plus, he's pretty good at handling the pitchers and controlling the game."
Span went 1-for-5 with an RBI double in the Twins' 7-5 win over the Royals on Sunday. But he was caught in a rundown on his seventh-inning double, as he fell down while trying to reach third base.