Here is the 2014 official new rule on home-plate collisions, reprinted directly from MLB:
Major League Baseball (MLB) and the Major League Baseball Players Association (MLBPA) have officially negotiated the addition of Rule 7.13, covering collisions at home plate, on an experimental basis for the 2014 season, the parties jointly announced today.
In 2014, the rule being implemented by MLB and the MLBPA (set out below) will prohibit the most egregious collisions at home plate. The new experimental rule sets forth that:
A runner attempting to score may not deviate from his direct pathway to the plate in order to initiate contact with the catcher (or other player covering home plate). If, in the judgment of the Umpire, a runner attempting to score initiates contact with the catcher (or other player covering home plate) in such a manner, the Umpire shall declare the runner out (even if the player covering home plate loses possession of the ball).
Unless the catcher is in possession of the ball, the catcher cannot block the pathway of the runner as he is attempting to score. If, in the judgment of the Umpire, the catcher, without possession of the ball, blocks the pathway of the runner, the Umpire shall call or signal the runner safe.
In determining whether a runner deviated from his pathway in order to initiate a collision, the Umpire will consider whether the runner made an effort to touch the plate, and whether he lowered his shoulders or pushed through with his hands, elbows or arms when veering toward the catcher. The rule that will be in effect in 2014 does not mandate that the runner always slide or that the catcher can never block the plate. However, runners who slide, and catchers who provide the runner with a lane to reach the plate, will never be found to be in violation of the new rule. Beginning immediately, Clubs will be required to train their runners to slide and their catchers to provide the runner with a pathway to reach the plate at all levels in their organizations.
MLB will distribute training materials throughout Spring Training and discussions on the new rule, including the retraining of catchers and base runners, will be held during MLB’s meetings with managers in the weeks ahead. Additionally, MLB and the MLBPA will form a committee of players and managers to review developments as the season progresses and to discuss the possible application of the new rule in 2015.
Finally, instant replay will be available to review potential violations of Rule 7.13. The Umpire Crew Chief will have discretion to invoke instant replay in order to determine whether Rule 7.13 was violated.
OFFICIAL BASEBALL RULE 7.13