The center fielder made a terrific grab on the warning track of a liner off the bat of Matt den Dekker that earned a standing ovation from spectators and high-fives from several teammates Tuesday night.
Span, who has a history of concussion problems, walked slowly back to the dugout after the play. He then headed toward the clubhouse with a team trainer.
Due to be the NL East champions' second batter in the third inning, Span was replaced by Michael Taylor.
Span entered the game leading the Nationals with a .298 batting average and 31 steals.