How NFL rule changes for 2021 will impact the game: Fewer low blocks, expanded review and balanced holding calls

Most of us look at NFL rules as a list of prohibitions. Teams see them differently. For them, the rulebook is a runway toward competitive advantage, and they focus more on what it allows.

In 2021, that means figuring out how to best exploit a rule change that imposes new limits on low blocks. It means compiling dossiers on the league office employees who will make replay decisions following the retirement of senior vice president Al Riveron. And it means getting an understanding of how officials will use in-stadium replay officials in real time for help in making certain calls, per a new rule.

To better understand the insight teams have been developing this summer -- you know they aren't sharing it publicly -- we picked the brain of retired NFL referee and current ESPN officiating analyst John Parry. Defensive backs, Parry believes, will be disproportionately impacted by the low block rule, giving offenses a lane for more effective outside runs and screen plays. Parry also suggested that unexpected uncertainty about the replay process could make coaches less willing to challenge plays, and he said there is "a 100% chance" that referees will use their replay officials for more than the new rule allows.

We published a full accounting of every 2021 rule change this spring, and what follows is an edited version of questions posed to Parry about how they might impact the game and playcalling in 2021.

Seifert: Let's start with low blocks. Starting this season, blocks below the waist will be allowed only within a newly-created tight end box, defined as 2 yards outside the offensive tackles and 5 yards on either side of the line of scrimmage. That is the only area where linemen can cut block and defenders can go low. Where does the upper hand go?

Parry: The running game, certainly. To me, this rule has created a matchup advantage for the big offensive lineman who is coming to the perimeter on the outside run or the screen play. You get that big guy coming to block people who don't have an option for taking on the block. That's something teams can leverage and exploit. You might see offensive coordinators moving more of their run game to the outside for that reason. Maybe that's part of the reason why Andy Reid went out and got a bunch of new linemen in Kansas City.

Seifert: But wouldn't the linemen also be disadvantaged? They've lost the cut block out there.

Parry: To me, the offensive guy always had multiple options for that block, based on angles, speed and where the defender is. He could choose to cut block or stay high and just run over the defender. He has options. But the defender, as I see it, has only one now. That's to stay high, and based on the size and weight differential, that may not end so well.

Seifert: This rule is presumably about protecting players from lower-body injuries. Is there something special about the interior of the tight end zone that makes it safe to cut block or for defenders to go low in that particular area?

Parry: Sometimes when the league discusses rule changes, they leave meat on the bone and don't go far enough. I guess I would have liked to have seen the data they used for this, but I would not be surprised if down the road, assuming players adjust to this as they usually do, they say you can't block low anywhere on the field. Maybe they didn't go far enough this time. Maybe they did. Maybe in a few years we'll see the box disappear altogether.

Seifert: Another change that has seemed possible in the near-future is a sky judge -- someone who could make officiating calls based on what they see on a television feed in the sky box. The NFL still hasn't moved in that direction, but they did come up with a way for the existing replay official to help referees on certain objective calls. Will this help?

Parry: The intent is to fix things that are very specific, very clear and objective. Is the foot out of bounds? Is the ball clearly out? The intent is to move the game along correctly without the coach needing to use a challenge. But it should really only be used as a safety net and a backstop. If we put too much pressure on somebody upstairs, most of whom have never been on the football field as an official, the end result long-term will not be good.

Seifert: Former NFL officiating chief Mike Pereira has been pretty public over the years in saying that referees were already seeking and receiving help from replay officials during the game through their wireless headsets, despite no rule that allowed it. Has that been what you've seen and experienced?

Parry: Yes. We see officials huddle. We see hands on the hips and on the earpiece, and that's because they're talking to this individual in the press box. And because it is loud, they continue to hold that earpiece into the ear so they can hear it better, and they're asking more questions to them.

Seifert: So now that cooperation on certain types of calls is allowed, what are the chances that officials tap their replay officials for help on plays that aren't covered by this rule?

Parry: 100%. I can tell you from my years on the field, we did it. They don't always have help to give, but officials are going to ask for it. Believe me, they've been using it. When they put an earpiece and a way to communicate between two human beings, they're going to use it. That's happened since they put the earpiece in the officials' ears years ago. You would be amazed what you would hear if you put those earpieces on.

So yes, I believe that the seven officials on the field and the replay booth will use it for anything and everything they want to use it for. I can tell you from experience that that has been done.

Seifert: So the replay official in the past was being asked about calls such as pass interference and unnecessary roughness, neither of which are covered under this rule?

Parry: Yes. I'll give you a specific example. The last regular-season football game I worked was in Philadelphia in 2018. Houston Texans pass-rusher Jadeveon Clowney comes off the edge on a 2-point try, grabs and twists Eagles quarterback Nick Foles' face mask. But because I'm standing behind the quarterback at an angle and he crouches down, I can't see it. I can feel that it's happening, but I can't see it, so I can't call it.

So on the communication system, I pushed the button to the replay official. I have my hand on the flag. I say, "If you get a replay and it's a face mask, tell me and I'll throw the flag." But there were crickets. Television didn't have a shot of it. I'm watching the Jumbotron, and it's clear as day. If TV had had it, I was throwing.

Seifert: That seems like an opaque way of getting to the result everyone wants as often as possible: The correct call being made without going to a formal replay review. But when there is a review in 2021, the process will be a bit different. Former senior vice president of officiating Al Riveron, who had final say over all reviews in recent seasons, has retired. The NFL has said that two other senior vice presidents, Walt Anderson and Perry Fewell, will have responsibility for decisions but haven't laid out details of the process. Shouldn't we -- and teams -- know more about it by now?

Parry: Yes. That bothers me. Every team wants to see consistency, and they want to be able to find correlation to previous calls. For example, if a similar play was overturned three weeks ago, teams can feel comfortable challenging it today. I'm not suggesting there can't be a group working on it, but somebody has to be there to make the final decision that can say, "Ok, two weeks ago we had that same play in Green Bay, and we need to be consistent, and here is what we're doing."

Seifert: Walt Anderson is a former referee, and Perry Fewell is a former coach, so neither of them are replay experts, per se. What does that mean to you?

Parry: I'll put it in the coaches' world or team world. If Fewell with a coaching background were in charge of replays, he would look at them differently than Anderson, who was an on-field official. They have a different lens. So I think coaches would want to know who is making the final call. That's going to affect how they go about deciding whether to challenge. That's valuable information because they have a different lens.

Seifert: A final element of competitive advantage this summer is the NFL's ongoing efforts to calibrate offensive holding. Last season, officials threw 40.7% fewer flags for offensive holding than they did in 2019, and that's a big reason why the league set scoring records. The competition committee vowed to study the calls and create a standard for what teams can expect in 2021. What do you think that will be?

Parry: We had a couple years where it was crazy, and we called everything, and I was part of that. Then we had a year last year where it was like, "Where did it go?" Holding was non-existent. I think they will attempt to find a balance north of the number that they had last year and way south of where it was when we were crazy busy.

I still think there are some officials who will walk onto the field, and no matter what they've heard, they've got 30-35 years of experience and know what a hold is. They know when it impacts a play and when it doesn't, and they'll call them this season. That's what they're out there for. There are senior people working this game who believe that, and I think the league will work to find a balance of when and when not to call it. It's gone way too far in both directions in recent years, and they know they need to find balance.

Seifert: But don't most fans like it the way it was last year?

Parry: It appears most people bought into the numbers that were created last year. Everybody likes the fact that there is less holding, fewer fouls. The game moves along better. But when the game is not officiated correctly based on the rules as they are written, the game changes -- and often times not for the better. Sometimes the bad guy has to win to make the story exciting, and the bad guy is the defender. There are teams that built their defenses based on incredible pass-rushers that were held all season, without it being called. I think the league will look for more balance to make it more fair this season.