MLB announced that expanded instant replay will be tested for the first time during game action next week in the Arizona Fall League:
New review procedures for expanded instant replay will be game-tested during play at the Arizona Fall League (AFL) in five games that will be televised live on MLB Network from Tuesday, November 5 through Saturday, November 9. …
AFL Umpires will be assigned to the games, which will be observed by select MLB officials and Major League Umpires. Plays in AFL games will be called and challenged under the protocols of the newly designed instant replay plan that is now under consideration.
Should make for riveting television!