CURVE ON, PUT A

a coined phrase meaning to add some unexpected thing or datum into something; to alter or change something from its normal course of action or state. This phrase alludes to the game of baseball in which a player (called the pitcher) throws a ball towards a member of the opposite team who tries to hit it with a bat. To make it difficult for the batter, the pitcher can throw the ball so that it "curves," and does not follow a normal or expected course.