MLB to Exapnd Instant Replay in 2014 - UPDATE

[tmagan]

A couple of questions:

1) Bottom of sixth, two out, close play at first, runner ruled out to end of inning, right after the opposing pitcher throws his eight pitches, the manager comes out and challenges the call saying he was safe. Is the challenge allowed, when is the cut off point where challenges aren't allowed?

2) What is the standard for overruling a call. When a call that should be overturned isn't, who in the Commissioner's Office will take the blame?