“Timing a Ball: This is done when you so time the swing of your bat to meet the ball as to hit it at a right angle to the line of your bat, and so as to hit the ball in the centre.” Henry Chadwick, Chadwick’s Baseball Manual, 1874.
Previous earliest use (Dickson Baseball Dictionary, 3rd edition, 2009):
1ST USE. 1887. “The natural swing of his [the batter’s] arms bringing the bat forward to meet the ball” (St. Louis Globe-Democrat, Jan. 30).