In other words, runners will still be ruled out, as in pre-2014 baseball, if the catcher gains possession of or imminently fields the throw before the runner arrives at home plate.
MLB Executive Vice President of Baseball Operations Joe Torre's words:
If the runner would have been called out notwithstanding the catcher’s improper positioning in front of the plate, the out call will stand.The clarification references hindrance and impedance, both elements of obstruction, suggesting in a sense that umpires may indeed adjudicate Rule 7.13 using the same principles that would otherwise apply to obstruction (or interference in the case of a runner deviating to contact the catcher) pursuant to Rule 2.00.
The only difference, naturally, is that Rule 2.00 [Obstruction] and [Interference] are not reviewable while Rule 7.13 is subject to Replay Review.
Tuesday night's Rule 7.13 review in New York resulted in a confirmed out call at home plate, with replay officials ruling that the baserunner would have been called out despite the catcher's positioning.
Video: Rule 7.13 Crew Chief Review highlight reel, featuring ejections and overturns (MLBAM)
Video: Greg Amsinger, John Smoltz and Harold Reynolds discuss the 7.13 clarification (MLB Network)