• The adoption of a no-pitch intentional walk. Managers will signal to the home-plate umpire their decision to intentionally walk a batter, and the umpire will immediately award first base to the batter.
• What the rules changes mean
• Managers will have 30 seconds to decide whether to challenge a play and invoke a replay review.
• When a manager has exhausted his challenges for the game, crew chiefs may invoke replay review for non-home run calls beginning in the eighth inning, instead of the seventh inning.
• With some exceptions, replay officials in the Replay Operations Center in New York will have two minutes to render a decision on a replay review.
• Teams may not use any markers on the field as points of reference for fielders' defensive positioning. This issue became newsworthy last May, when the Mets contacted MLB about a Dodgers' request to make marks on the Citi Field grass to identify desired positioning for their outfielders. Rules 3.09 and 3.10 prevent clubs from leaving equipment on the playing field, but this modification makes it more clear that these specific kinds of markers are prohibited.
• An addition to Rule 5.07 stipulates that a pitcher may not take a second step toward home plate with either foot or otherwise reset his pivot foot in his delivery of the pitch. If there is at least one runner on base, such an action will be called a balk under Rule 6.02(a). If the bases are unoccupied, then it will be considered an illegal pitch under Rule 6.02(b). This adaptation would appear to be a response to Padres reliever Carter Capps' unusual and controversial hop-step delivery.
• An amendment to Rule 5.03 requires base coaches to position themselves behind the line of the coach's box closest to home plate and the front line that runs parallel to the foul line prior to each pitch. A base coach may leave the coach's box to signal a player once a ball is in play, provided that the coach does not interfere with the play.
Anthony Castrovince has been a reporter for MLB.com since 2004. Read his columns and follow him on Twitter at @Castrovince. This story was not subject to the approval of Major League Baseball or its clubs.