Women who seek out jersey wearing athletes (i.e. bicyclists, basketball players, football players, etc.) for sexual encounters, essentially sports groupies. See: Bullpen Beef
The Jersey Jumpers were sitting in the bleachers trying to hit on members of the bicycling team, just like the Bullpen Beef we saw the night before hitting on the Oakland A's bullpen players.
by Captain Incredible x Infinity February 12, 2014