rally cap

noun1

1. •
   (US) A baseball cap worn inside-out and backwards, or in another unconventional manner, by players or fans, as a talisman in order to will a team into a come-from-behind rally late in the game.

   • His cap was turned backwards in the manner of a catcher or a rally-cap, though he had no intention of catching and there certainly wasn't a rally going on. — 2001