The officials have been locked out since June, when they and the league couldn't agree on a new collective bargaining agreement. In the officials' absence, replacement refs were brought in from lower college levels or from other leagues such as Arena Football.
The league and the officials' union met on Sunday without making any progress. The players' union also called on the 32 team owners to end the lockout because it is compromising the integrity of the game.
Packers guard T.J. Lang tweeted that they were robbed "by the refs. Thanks NFL."
In Sunday's Baltimore-New England game, aggro followed even insignificant plays. One TV analyst called it the substitute-teacher syndrome: See how much you can get away with before the real thing returns.
"Nature says for us that we're going to go out there and push the limit regardless," Minnesota linebacker Chad Greenway said. "If they're calling a game tight, if they're calling a game loose, it's going to be pushed to the limit. You are pushing it to the brink. If things are going to be called easier, and in some situations I feel like they've been less lenient, too, you've just got to play and see how (it's being called)."