In baseball, the ball is put in play by the defense, and only the defense is allowed to touch the ball. In football, you score with the ball and without the ball you can't score. In baseball, the ball prevents you from scoring. In football the team is run by a coach who wears street clothes. In baseball the team is run by a manager who wears the same uniform as the players.
Baseball begins in the spring, the season of new life.
Football begins in the fall, when everything is dying. In football you wear a helmet. In baseball you wear a cap. Football is concerned with downs. In baseball, you're concerned with ups.