Denver's other two proposals involve expanding the scope of automatic instant-replay reviews to include all fourth-down plays that fail to reach the line to gain and all extra-point and two-point conversion attempts. The latter came up during the Broncos' Week 11 win over the Chargers in Los Angeles last November.

These represent two of nine proposed rules changes that involve instant replay. These represent more than half of the 16 overall proposals.

The Competition Committee submitted two proposals involving instant replay. Both of them incorporate the Broncos' proposal regarding automatic reviews on extra points and two-point conversions. The first Competition Committee proposal would make pass-interference penalties reviewable. The second proposal would make pass-interference, roughing-the-passer and hit-on-a-defenseless-player penalties subject to coaches' challenges and review.

Any expansion of instant replay could result in slowing down the game, which is part of the balance that will be considered.

Kansas City proposed three changes to overtime rules, the most notable of which would guarantee each team one overtime possession. Overtime ideas were discussed "at length" by the Competition Committee said McKay.

"We'll see how the proposal fares," McKay said. "We've had a lot of discussion about the OT procedures over the years, and it's been a good one driven by data."

"Data tells us since 2001, 80 percent of the time, both teams touch the ball [in overtime]," said Troy Vincent, the NFL's executive vice president of football operations. "And just putting on my old cap, you've got to play D. You've got to stop the offense, and when the offense gets on the field, you've got to score.

"There's something about that -- not just tradition -- but you've got to play ball. Statistically, when people raise it, it's because they fell short on the other end. They didn't, the team that won the toss, took the ball down the field, which happens maybe 20 percent of the time. Other than that, you've got to play ball."

McKay also said the NFL will experiment with an eighth official during the preseason, but the league is still trying to determine where on the field that official would be aligned.

But the key is that an eighth official would be on the field. McKay said there was "no support" in the Competition Committee for having a "sky judge" that could assess penalties from a press-box perch.