Examples:

• Good thing you're on the ball when it comes to advertising.
• I need to be on the ball all the time.
• It's just that I know Marissa, and she's on the ball.
• If you were on the ball, this wouldn’t have happened.
• On the ball of your foot, come on.
• I'm just saying... keep your eye on the ball, Coach.
• Don't you want to keep your eye on the ball?
• Keep your eye on the ball and swing with this leg.
• Way to keep your eye on the ball, Doug.
• To get your name on the Ball of Fame?