Major League Baseball is making some changes to its new rule on home plate collisions.  A formal step was taken Tuesday to announce that the rule would no longer be enforced on force plays, such as when a runner at third base is attempting to score with the bases loaded.  Catchers are now permitted to have a foot on home plate, as that would be required to complete the out anyway.  An overturned call in a recent game between the Pirates and Reds stirred controversy over the new rule.  Rule 7.13 will still prohibit catchers from blocking home plate without possession of the ball on any other type of play.