Few people in or around the NFL, it seems, were pleased with how the new rule making pass interference reviewable by instant replay worked during the regular season.

Coaches were perplexed. Fans griped. The NFL initially said it was up to the coaches, who pushed hard during the offseason for the new system, to adjust to how the rulings were being made by the league’s officiating department in New York. Eventually, league leaders accepted that the system did not function as intended when the owners ratified it in March in the wake of the officiating blunder in last season’s NFC championship game in New Orleans.

The NFL will consider possible tweaks to the replay-for-interference rule in the offseason. The system faces a renewal vote by the owners in March, meaning it could be scrapped after only one season.

In the meantime, the games that matter the most are at hand, and fans, players and coaches have little reason to trust that the system will function smoothly during the playoffs.

What, exactly, is the rule?

Both interference calls and non-calls by the on-field officials are subject to instant-replay reviews. Coaches can make interference-related challenges in the first 28 minutes of each half. In the final two minutes of each half, an interference-related review must be initiated by the replay booth. Each team continues to have two replay challenges per game and receives a third challenge if it gets the first two correct. Scoring plays and turnovers are automatically reviewed. The reviews are overseen by Al Riveron, the NFL’s senior vice president of officiating, and other members of the league’s officiating department.

Why did the NFL make the change?

The officiating gaffe late in the NFC championship game that sent the Los Angeles Rams to the Super Bowl over the New Orleans Saints prompted the move. The Rams’ Nickell Robey-Coleman crashed into the Saints’ Tommylee Lewis before the football arrived on a key play late in the game, and no penalty was called, either for interference or for an illegal hit.

The competition committee’s long-standing policy was to keep judgment calls from being reviewable by replay, but the league was under public pressure. Saints Coach Sean Payton is a member of the competition committee, and he and other coaches lobbied for something to be done.

Coaches initially favored a system that would use a “sky judge,” a member of the officiating crew who would be stationed in front of a monitor in the press box at each game and empowered to correct obvious mistakes by the on-field officials. But the league and competition committee wondered where they would find enough qualified officials to enact such a system. The owners settled on this system and put things into the hands of Riveron.

How did it work in the regular season?

The results were spotty at best. On some prominent plays on which interference wasn’t called when it probably should have been, replay allowed the on-field non-call to stand. That included a play during a Texans-Ravens game in November in which Houston wide receiver DeAndre Hopkins was all but tackled in the end zone by the Ravens’ Marlon Humphrey, with no flag and no replay reversal. That play led to the NFL’s private acknowledgment that the system wasn’t working.

There also was a key play late in the final game of the regular season, on which the San Francisco 49ers probably got away with defensive pass interference in the end zone in the closing moments of a narrow victory over the Seattle Seahawks, and there was no replay reversal. The Seahawks ended up coming up a few inches shy of a go-ahead touchdown on their final offensive play in a game that decided the NFC West title and gave the Niners the NFC’s No. 1 playoff seed. Seahawks Coach Pete Carroll said later the NFL wished that interference had been called against the 49ers on the play.

Overall, coaches and players said it was difficult to figure out what the standard was for a reversal.

How many were overturned?

There were 101 interference-related replay reviews during the regular season, and 24 of them resulted in the on-field call being reversed.

There were 21 reversals among 74 reviews of plays on which interference was not called on the field. There were just three reversals among 27 reviews on plays on which interference was called on the field.

No coach won a challenge all season (in 13 tries) of a play on which defensive pass interference was called by the on-field officials.

What were the biggest problems?

Just as the competition committee had feared, a subjective call such as pass interference does not necessarily become less subjective on replay. The idea was to eliminate the obvious mistakes. If a handful of plays, such as the Hopkins play against the Ravens, had been decided differently, the overall feeling about how things went might be different.

Riveron struggled to make consistent rulings, many around the league felt, just as he struggled a couple years ago with plays that involved catch or no-catch determinations. That led to a change in the NFL’s catch rule. This time, it’s not clear what can be modified to make the rule work better.

“It’s no longer like it was before when we were looking at a line and whether two feet were in or not in, whether the ball crossed the line or did not cross the line,” Atlanta Falcons President Rich McKay, the chairman of the competition committee, said at an owners’ meeting last month in Dallas. “This is a subjective review of whether there was clear and obvious, significant hindrance of a receiver.”

Troy Vincent, the NFL’s executive vice president of football operations, said at that owners’ meeting that the league would “look at everything” in attempting to address its ongoing officiating controversies this season. That all-encompassing review could include an examination of whether Riveron will remain in charge of the officiating department.

How will it work in the playoffs?

That is anyone’s guess. If there’s a significant instant replay ruling related to pass interference during the postseason, it could sway opinions about how things went with the new rule this season. McKay said last month he was taking a wait-and-see approach on whether the rule will be renewed for another season.

“There’s no question there’s been angst,” McKay said then. “I’ve felt the angst. … But it’s a new rule, a big change, something we haven’t done before.”