Major League Baseball and umpires are expected to announce a plan for crew chiefs to wear a microphone and explain replay rulings to fans.

One scenario would have umpires start at the All-Star Game on July 11 in Miami, tweak the process over the season's second half and then go forward with the experiment in the playoffs.

The umpires are in the middle of their five-year labor deal and any change would involve negotiations, plus a comfort level on both sides.