ENGLEWOOD, Colo. -- Of the rules changes and points of emphasis presented by back judge Scott Helverson and three other officials Thursday, the one with the most profound impact on most games will be the extra emphasis placed on illegal contact by defenders on potential receivers and offensive pass interference.

But the one that could attract the most attention is what NFL vice president of officiating Dean Blandino describes on a video shown to players and media -- which can be watched above -- as "zero tolerance for unsportsmanlike conduct -- particularly verbal abuse at an opponent." This includes slurs in regard to race and sexual orientation, or other verbal abuse.

The question of what constitutes "verbal abuse looms. This is articulately valid regarding with the "n-word," which can be heard in game-time combat -- and often not as a pejorative. 

"I don't think there's ever a good time to use the 'n-word,'" said Helverson, one of four NFL officials to work Broncos practice Thursday.

But 15 yards is assessed depends on the context, which puts NFL officials in an unenviable position, of trying to judge the intent.

"I think it (context) always matters," Helverson said. "Again, you just have to know the circumstance, who said it, why they said it, and in what circumstances.

"We don't know how it's going to work out. (With) the education that we bring in the preseason, along with these videos, and help from the coaching staff, hopefully we can eliminate it."

But before that can happen, officials have to know the difference between insult and affection between players who are on opposite sides now, but who might have played against or with each other growing up or in college.

"That's a problem for us," Helverson said. "One thing, the players, trust us, (saying), 'Oh, he's my buddy,' 'He's my friend,' 'I played with him in school.' We don't know that. That's the kind of education we have to teach them when we're here and when we go through preseason and the regular season."

By comparison to that minefield of context and subjectivity, the re-emphasis on illegal contact and offensive pass interference appears as clear as the skies often seen above Denver. Helverson made it clear that every bit of contact more than five yards beyond the line of scrimmage -- assuming the quarterback is in the pocket with the football -- will be penalized.

It continues the evolution of how illegal contact is administered.

"Three or four years ago -- or maybe even five -- we really got into the jersey pulls," Helverson said. "We finally got away from it because the jersey pull didn't necessarily take a stride away from the receiver.

"Now they want to clean it up, make it more of a foul that everybody understands. You pull the jersey, and it's a foul, regardless. So we've always had that rule, now it's a point of emphasis.

"Sometimes we wouldn't call illegal contact unless it displaced a player. Now they want to get into if he's making any kind of contact beyond five yards, that we're going to call that."

There is the risk that teams could simply chuck, shove, grab and obstruct receivers beyond the five-yard mark on every play, daring officials to try and call every infraction, knowing that they might miss some. Another risk is that if every instance of illegal contact is called, the games, already creeping beyond the three-hour, 10-minute mark, will become herky-jerky slogs that have no flow, approach three and a half to four hours, and become interminable for audiences both in the stadium and on television.

"We don't really concern ourselves with time and TV production. We officiate the games, and that's all we do," said Wayne Mackie, a head linesman. "We keep the integrity of the league and the integrity of the game up. I couldn't care how long the game went. If it goes three and a half hours, it goes three and a half hours. We really don't care.

"We just enforce the fouls that we are taught to enforce."

Other changes and points of emphasis include:

PRE-SNAP MOVEMENT ON THE OFFENSIVE LINE: The NFL-produced video showed to teams used a Broncos play to illustrate what will be called a penalty, when center Manny Ramirez bobbed his head before sending a shotgun snap to Peyton Manning. "The whole thing is how quickly they're doing it, and when are they doing it. So they want that cut back," said umpire Richard Hall. "If they're moving their rear end down and they don't snap the ball, it's a foul. The center has almost got to become still the whole time after the initial set."

ILLEGAL USE OF HANDS: Direct and forcible contact to the head, neck or face of the opponent -- regardless of whether it pins the head back or not -- will be called. The illegal use of hands "in close line play" will also be closely monitored.

INSTANT REPLAY: Officials can consult with senior members of the officiating department, who will sit near a bank of television monitors at the NFL office. This is similar to the communication that exists between Major League Baseball's umpires on site and umpires at a command center in New York City. In MLB, the umpires in New York make the calls; in the NFL, the final judgment will continue to belong to the on-site referee.

The use of replay was expanded to include plays involving the recovery of a loose football in the field of play.

CLIPPING: Rolling up on the side of the legs of a defender is now considered clipping, punishable by a 15-yard penalty. This expands the definition of the rule, from being just for rolling up the back of the leg.

SACKS: The game clock will now continue to run for sacks made outside of the two-minute warning in each half.

EXTRA POINTS: In the Hall of Fame Game this weekend and the first two full weeks of the preseason, extra points will be executed with the ball snapped from the 15-yard-line, instead of the 2-yard-line, as is currently the case. Two-point conversions will not move.

UPRIGHTS: They were extended an extra five feet.

SPORTSMANSHIP: Using the pylon, crossbar, goalpost or any other object as part of a celebration is now a 15-yard unsportsmanlike conduct penalty. So we have seen the last of Julius Thomas' dunks over the crossbar, unless he wants to draw a penalty.