INTENTIONALLY DEFLECTING COURSE OF BALL
Official Baseball Rule 6.01(a)(2) provides that the batter or runner is out for interference if he intentionally “deflects the course of a foul ball in any manner.” While picking up a foul ball or otherwise touching it may not, by such act itself, actually deflect the course of the ball, an umpire may judge such act as deflecting the course of the ball if, in the umpire’s judgment, the ball might have become a fair ball had it not been touched.
It would be better if no member of the offensive team picked up or otherwise touched a foul ball. There is no objection to a coach returning a foul ball to the umpire after it has passed first or third base, but the coach should not touch a ball that possibly may go fair. See also Official Baseball Rule 5.09(a)(9).