As we all suspected it appears the play was called incorrectly

Play: Seahawks offensive lineman J.R. Sweezy penalized for unnecessary roughness in live action
Referee: Tony Corrente
Analysis: With 8:02 remaining in the third quarter, Packers linebacker Clay Matthews sacked Seahawks quarterback Russell Wilson for a 15-yard loss. Matthews landed on top of Wilson during the play, at which point Sweezy dove into Matthews' back to peel him off the pile.

Corrente's crew correctly penalized Sweezy, but the Packers declined to enforce. Why? Because Corrente did not rule it a "dead ball foul," which would have tacked the 15-yard penalty on top of the 15-yard sack and led to a second-and-45 situation. Instead, he apparently believed Sweezy hit Matthews before Wilson was down.

Viewed on replay, it's clear Wilson's knee had touched the ground before Sweezy hit Matthews. Rule 7, Section 2, Article 1 directs officials to call the ball dead and the down complete "when a runner is contacted by an opponent and touches the ground with any body part other than his hands or feet. The ball is dead the instant the runner touches the ground."

The Packers should not have been in position to choose between declining the penalty or giving the Seahawks another first-and-15. It's fair to note, of course, that the Packers could have made the call moot had they stopped the Seahawks on an ensuing third-and-19 two plays later.
http://espn.go.com/blog/nflnation/po...t-on-tom-brady