The NFL Live crew is on board with new replay rules, but it has some concerns over officiating ruining the flow of the game. (2:00)

As spring turns into summer, a fierce debate is raging among NFL decision-makers: Who should stop the game to review a potential pass interference penalty, and when?

The question might seem minor, but it pushes to the core of whether expanded replay can be effective at the NFL level. And for the second consecutive year, the league's competition committee is attempting to reverse-engineer a major rule change.

The new process for reviewing pass interference, approved by owners in March, followed the structure of the existing system. Coaches would challenge calls until the two-minute warning of either half, after which responsibility would be shifted to the on-site replay official. While coaches would be checked by the existing two-challenge limit -- plus a third if the first two were right -- the replay official could initiate reviews whenever necessary during the final two minutes and overtime.

Since then, however, concern has grown about the number of stoppages replay officials might feel compelled to make, especially with the addition of no-calls to the list of reviewable plays. Owners granted the competition committee authority last month to tweak the system, if needed, to extend the coaches' challenge for pass interference into the final two minutes and overtime.

But as it turns out, some coaches don't want that responsibility. During conference calls last week, according to multiple sources, some of them pushed back, in part because of the impact on timeout and challenge strategy. (A coach can't challenge if he's out of timeouts.) This response mirrors the proposal most coaches advocated in March -- to convert the replay official into a "sky judge" who would alert the on-field referee whenever an egregious mistake was made.

So with six weeks until the first training camps open, the competition committee must decide whether to impose an unwanted obligation on coaches or risk a significant rise in stoppages during a game's most dramatic moments.

The standard for overturning an officiating decision is well-known: "clear and obvious" evidence of a mistake. But as we noted last month, the standard is far less clear for stopping the game to determine if that kind of mistake has occurred. It is one thing for a replay official to notice ball movement as a ball carrier is tackled, and then to initiate a review for a possible fumble call. It is quite another to decide in real time whether contact between a receiver and defensive back merits a review to determine if one player "significantly hindered" the other from playing the ball, the standard for any pass interference penalty.

The majority of NFL replay officials have never officiated a game on the field, where they would have been asked to make that type of subjective decision with speed and accuracy. Because there is at least some level of contact on most passing plays, it's not difficult to envision a review for most contested passes during a two-minute drill.

"The replay official's job is to officiate each and every play in their own little universe," said retired referee John Parry, now an ESPN rules analyst. "He or she must ask, 'Is there enough for me -- with smoke on the field [after a celebration], players raising their arms, all those things that we see -- to stop and take a look at it?'"

Faced with a similar dilemma as it developed its own pass interference review process, the Canadian Football League put the authority squarely with coaches. Darren Hackwood, the CFL's senior director of officiating, considers that structure an important pillar of what the league now considers a successful initiative.

"Our game is so passing-heavy," Hackwood said last month, "that we would be slowing the game down a bunch of times if we allowed the replay official to do that. So it's on the coaches to challenge. Whatever the trigger would be to initiate a review [from the replay official], we would be going to it too much."

Generally speaking, of course, coaches like to save their timeouts. They don't throw their challenge flags nearly as many times as the public debate would suggest. Last year, for instance, they challenged 147 plays during the regular season and playoffs for an average of 0.28 per game per coach, according to ESPN Stats & Information. There were only 19 instances of a coach using two challenges in a game, in 534 opportunities, and since 2001, coaches have used three challenges in only nine games.

But the addition of pass interference to the review system will add opportunities, and perhaps pressure, for coaches to challenge more plays. If the competition committee extends the coaches' responsibility into the final two minutes, they would risk burning a saved timeout for reviews, potentially leaving them with fewer options in clock management.

Perhaps most importantly, eliminating the booth review would leave the league unable to reverse an egregious call in a key spot -- precisely the reason the rule was approved in the first place -- if a coach is out of timeouts or challenges or both.

New Orleans Saints coach Sean Payton, a member of the competition committee, advocated strongly for the March replay proposal. But he also echoed other coaches whose ultimate, if not immediate, goal is for a sky judge to handle reversals of obvious mistakes.

"We're going to have a point," Payton said. "It's not this year, not today, but an eighth official upstairs is going to allow this game to flow. He's going to buzz that buzzer when he feels a certain level of mistake has been made."

There is significant disagreement among NFL officials on the practicality of a sky judge, and for now their concern rests squarely with the 2019 season. After fiddling with the new helmet and kickoff rules throughout last summer, and issuing a clarification on roughing the passer in September, the competition committee wants to settle the rules for reviewing pass interference long before training camps open.

Historically, coaches haven't won many battles over rules with league decision-makers. The choice appears to be between complicating traditional strategy and lengthening games, even if a sky judge one day renders the entire debate moot. Regardless, it seems clear that, one way or another, someone is going to be unhappy as the committee navigates this rule change to a workable position for the 2019 season.