PHOENIX -- Concerned with how it will be officiated, NFL owners delayed voting Tuesday on a rule change that would ban offensive players from using the crown of their helmets against defenders in the open field.
After approving two other rule changes to enhance player safety, they stalled on the more contentious issue. NFL senior vice president of football operations Ray Anderson said the owners plan to vote on it Wednesday before the meetings end.
The owners outlawed peel-back blocks anywhere on the field; previously, they were illegal only inside the tackle box. A player makes a peel-back block when he is moving toward his goal line, approaches an opponent from behind or the side and makes contact below the waist.
The penalty will be 15 yards.
"... Really, under no circumstances will you be permitted to block low below the waist when you're blocking back towards your own end line," said Rams coach Jeff Fisher, co-chairman of the competition committee.
Also banned is overloading a formation while attempting to block a field goal or extra point. Defensive teams can now have only six or fewer players on each side of the snapper at the line of scrimmage. Players not on the line can't push teammates on the line into blockers, either.
The alignment violation is a 5-yard penalty. The pushing penalty is 15 yards for unnecessary roughness.
"There were injuries, yes," Fisher said. "Talking to coaches and the players, it's just not something they look forward to doing. It's like, 'Oh, we scored again? We have to go out there and protect, kick an extra point or try?' "
Another discussed idea was the possibility of a "pickup game" concept being implemented for the Pro Bowl, a source told ESPN.com's John Clayton
The proposal called for Pro Bowl players first being selected, then team captains would be appointed and they would be involved in picking the players for their teams, the source said. That selection process could be involved in a television show a week or so prior to the Pro Bowl.
Nothing is expected to be done at the winter meetings and the source also questioned whether the owners would go for such a different idea.
Commissioner Roger Goodell has been down on the quality of the Pro Bowl for the past few years although he reiterated Monday he saw a better product this year. Still, Goodell would be willing to eliminate the Pro Bowl game at some point. A decision is needed soon on where the game will be played.
The NFL has also discussed rotating in places such as Phoenix, New Orleans, Miami and possibly the new stadium in San Jose, a source confirmed. If the game continues, it will be played the Sunday between the championship games and the Super Bowls because ratings for the Pro Bowl have been good.
But the potential change that has drawn the most attention -- yes, even more than eliminating the infamous tuck rule, which seems to be a foregone conclusion and will be voted on Wednesday -- is prohibiting ball carriers outside the tackle box from lowering their helmets and making contact with defenders with the crown.
New York Giants owner John Mara, a member of the competition committee that has recommended the change, said there was "a chance" a vote could be tabled until the May meetings in Boston.
"There was a spirited discussion," Mara said.
Many coaches have said they are concerned about officiating such a new rule.
"In all fairness, it's going to be tough on the officials, it's going to be tough to make that determination at live speed with one look," said John Harbaugh of the Super Bowl champion Baltimore Ravens.
Harbaugh noted that in the competition committee's examination of one week of play last season, it found five instances in which a ball carrier was not protecting the ball or himself and lowered his helmet to make contact with a defender.
Dean Blandino, recently promoted to vice president of officiating, noted that five in 16 games was significant enough to consider banning the act.
"We want to make a serious attempt to get the shoulder back into the game. We are not saying the ball carrier cannot get small. We are not saying the ball carrier cannot protect the football, because if he is going to go down to cover the football, if the shoulder goes down, we know the head goes down, we understand that.
"Protecting the football is OK, providing you do not strike with the crown of your helmet, and that is what we are trying to differentiate."
Blandino said the league wants flags thrown only on the obvious calls. He also said in cases in which a player is not penalized, he could still be subject to a fine if video review after the game determines he made contact with the crown.
The penalty will be a spot foul for 15 yards.
New senior director of officiating Alberto Riveron said if the offensive and defensive player are both committing the foul, it would be an offsetting penalty and the down replayed.
Riveron said the key to officiating the play is in showing the officials more plays that are legal.
"That will be a great way to train because, as we know it, most of the shots we have seen are legal, most of the contact is legal," he said. "We are trying to get that one individual situation where the head is lowered -- and you can see on the field, you can see a player put his head down -- and the contact is with the crown and you can see it."
ESPN.com's John Clayton and The Associated Press contributed to this report.