Implement a challenge system, MLB

[gumpire]

Hey guys; I'm a ASA slow-pitch softball umpire so claim no special knowledge or privilege - but I had an idea:

From what I saw on the replay of this event, it appeared that Mr. Joyce DID confer with his fellow umpires; that is what we all (umpires) should do if there is reason for us to believe we may have missed something.

Following all of that; why not make replays available to umpires to use to review a call when, and only when, THEY feel they might need that extra help?