After a close game decided by a questionable call, the conversation often turns to the topic of Instant Replay. This time, I’ll start it.

I’m not interested in rehashing the pros and cons of instant replay, which have been debated for years. The expansion of replay seems inevitable at this point. But as with most issues, the devil is in the details, and there does not seem to be a consensus on how expanded replay will work.

Who can initiate replay review? If managers can, do they get a certain number of challenges like in football? What calls can be reviewed? What happens when certain calls are overturned (e.g. a ball hit down the line with runners on base called foul that was actually fair)?

It's an interesting topic which I confess I haven't given a ton of thought to, but here's an initial stab. I'd be interested in hearing others' ideas on the subject.

Calls subject to review (at least the biggies, I know I’m missing some obscure ones here)

• Should be subject to replay review: fair/foul, safe/out on any base, retouch, catch/trap, fan interference, whether run scored before third out
  
• Should not subject to replay review: ball/strike, balk, catcher’s interference
  
• Not sure how I feel about replay review: foul tip on strike 3, hit-by-pitch
  

Who can initiate review

• Each manager gets 2 challenges, plus 1 additional if game goes into extra innings
  
• For non-scoring plays, there is a time limit of 3 minutes for video review. If they cannot find conclusive evidence to overturn it in that time, the call on the field stands
  
• Umpires can order review on scoring plays
  

Overturning a call

Put things where they would have been had the call been correct in the first instance. This will sometimes require umpire judgment (e.g. on overturned foul ball or catch calls). This is a tough one, but there could be general guidelines (e.g. ball in the corner – all runners get 2 bases, shallow outfield trap = 1 base). There will always be situations where this won’t be completely fair (e.g. Revere may be only allowed to go from first to third on a ball he would have scored easily on), but it’s better than getting the call completely wrong.