A motorized cart was driven onto the playing field from a left field gate between the fourth and fifth innings at Coors Field in Denver and was driven to third base-area stands, where a stretcher was passed several rows up into the crowd.
Judith Reese, 69, who had been struck by a foul ball from Colorado's Michael Cuddyer, was placed on the stretcher and driven back out through the gate as players and coaches watched.
Reese was treated for bruises at a nearby hospital and released, KDVR-TV, Denver, reported.
The game was resumed after a delay of 10-15 minutes.
The Rockies eventually lost to the Giants 7-0.