I think the rule has ALWAYS been there, but it hasn't been called. Now, when a drop on the transfer occurs, the umps are going back to the rule book and having to enforce it to make sure they get the call right.
Replay is great, but MLB has botched this thing in about a thousand ways. First off, coach challenges are stupid. Why did they take the stupidest part of the challenge system from the NFL? Why is it a coach's responsibility to get a play called correctly? I could go on, but eh.
"He's a *****. It's not that he was a *****, he is a *****, and that's why he hasn't won anything."