For the second consecutive weekend, a question of NFL rules -- and rule interpretation -- has produced a dominant postgame storyline. On Saturday night, the New England Patriots introduced an unprecedented scheme to create mismatches for their pass-catchers.

Five key questions arose the day after their 35-31 victory over the Baltimore Ravens:

Was the scheme -- four offensive linemen, with an otherwise eligible receiver reporting as the fifth ineligible player -- legal? Did it violate the spirit of NFL rules, if not a precise rule specifically? Did referee Bill Vinovich handle the surprise appropriately? Were the Ravens' objections justified? Will anything change next season as a result?

The short answer, from this vantage point less than 24 hours after the episode:

The Patriots' scheme was legal, even if it pushed the envelope on the NFL's attempt to legislate substitution deception out of the game. Vinovich followed protocol, which gives him discretion on how much time to allow a defense to react to substitutions. Ravens coach John Harbaugh erred by not calling a timeout to give his defensive players their assignments. Finally, it's likely that the NFL's competition committee will at least review the Patriots' formation this offseason to ensure it complied with the NFL's sportsmanship code.

Now let's take a step back and review what happened, with the help of the NFL rulebook and common sense.

On three plays in the second possession of the second half, the Patriots removed an offensive lineman and replaced him with a player who was wearing the number of an eligible receiver. On the first instance, for example, right guard Josh Kline left the field and running back Shane Vereen -- who wears No. 34 -- replaced him.

As required by rule Rule 5, Section 3, Article 1, Vereen reported himself ineligible to Vinovich and lined up in the slot to the right of the formation. The Patriots' line included only four offensive linemen, but it was a legal formation because it included five ineligible receivers. (The rule doesn't require Vereen to be tight to the line.)

Vinovich announced to the Ravens' defense that Vereen was ineligible, as required by the same rule. According to ESPN Patriots reporter Mike Reiss, within the stadium Vinovich could even be heard to tell the Ravens defense not to cover him. At the snap, Vereen ran into the backfield as if he was going to catch a lateral pass; in truth, his "route" was a decoy.

Understandably confused, the Ravens still covered Vereen and left open tight end Michael Hoomanawanui, who caught a 16-yard pass.

After the second such instance, Harbaugh ran onto the field and took an unsportsmanlike conduct penalty, he said later, so that he could implore Vinovich to provide the Ravens more time to adjust to the unconventional ineligible receiver. Harbaugh appeared to be referencing Rule 5, Section 2, Article 10, which begins:

"If a substitution is made by the offense, the offense shall not be permitted to snap the ball until the defense has been permitted to respond with its substitutions. While in the process of a substitution [or simulated substitution], the offense is prohibited from rushing quickly to the line of scrimmage and snapping the ball in an obvious attempt to cause a defensive foul [i.e., too many men on the field]."

The rule further calls for the umpire to stand over the ball until the referee has determined "that the defense has had a reasonable time to complete its substitutions."

This rule originated from the NFL's disapproval of "deceptive" substitution patterns. It wants to avoid strategies that quickly assemble a formation via new players and snap the ball before the defense can match up appropriately.

Did Vinovich give the Ravens enough time to react to a formation that put an ineligible receiver in the slot? Via the TV copy of the game, I counted roughly 10 seconds between the time of the first substitute and the snap. Was that enough time? Should Vinovich have instructed the umpire to stand over the ball while the Ravens identified, adjusted and possibly substituted?

Former NFL referee Jim Daopoulos, speaking Sunday morning on "SportsCenter," said anything longer would have effectively worked as a disadvantage to the Patriots.

In the end, Harbaugh should have called a timeout to organize and adjust to the surprise. He could have used that time to speak with Vinovich rather than sacrificing 5 yards (half the distance to the goal line) to do so. According to Harbaugh, Vinovich eventually said he would provide appropriate time moving forward, but by then the Patriots had already cashed in with one touchdown drive and the surprise element was concluded.

One of the primary jobs of the NFL competition committee is to ensure that league rules can't be manipulated to one team's advantage. The NFL rulebook is the most complicated in sports in part due to exceptions and caveats that have been inserted in reaction to similar instances. I'm sure the committee will review the Patriots' strategy, but from this perspective, it seems the most we can expect is a reinforcement that referees must give defenses appropriate time to adjust to substitutions.

The Patriots' reputation as NFL rule-pushers, punctuated by their 2007 discipline for videotaping opponents illegally, surely has played a role in Sunday's swelling emotions. In the end, however, there isn't much to dispute here. Their scheme was legal and sound. Vinovich handled it as well as could have been expected. A creative innovation caught the Ravens by surprise, and they didn't adjust in time. So it goes.