Mike Pereira, the former Vice President of Officiating in the NFL and current rules analyst at Fox Sports, took to Twitter to analyze the controversial Baltimore Ravens' game-winning field goal:

Just got back. Here is the rule on FGs. The entire ball must pass inside the outside edge of the upright.
— Mike Pereira (@MikePereira) September 24, 2012

A FG that goes over the top of an upright is not reviewable because you cannot determine when exactly the ball is directly over the pole
— Mike Pereira (@MikePereira) September 24, 2012

So that's the rule. I can't tell good or not but if I had to guess, I'd say it was good.
— Mike Pereira (@MikePereira) September 24, 2012