There's a problem with the NHL's changed offside rule for 2020-21 season

In a league that has constantly looked for ways to increase scoring — or at least pretended to do so — there is little more frustrating than a good goal getting overturned for a dubious reason.

Offside reviews are frequently the bane of otherwise entertaining games as officials spend minutes that feel like hours determining if a player’s skate was touching the ice behind the blue line as the puck entered the offensive zone. The NHL heard the lament from hockey fans and made a change.

No, they didn’t scrap offside reviews entirely, but they did get rid of the rule that a player’s skate has to be touching the ice in order to stay onside.

Here’s the new wording added to Rule 83.1:

“A player is on-side when either of his skates are in contact with the blue line, or on his own side of the line, at the instant the puck completely crosses the leading edge of the blue line. On his own side of the line shall be defined by a ‘plane’ of the blue line which shall extend from the leading edge of the blue line upwards. If a player's skate has yet to break the ‘plane’ prior to the puck crossing the leading edge, he is deemed to be on-side for the purpose of the off-side rule.”

Clear as mud?

The NHL also released a video explaining the new rule which helps clarify things, such as the location of the “leading edge” of the blue line, which is evidently the edge closest to the goal.

UPDATE TO @NHL RULE 83.1 (OFF-SIDE): Beginning in the 2020-21 regular season, a player's skate will not have to be in contact with the blue line in order to be on-side.

Updated language: https://t.co/gp5npRIw9k pic.twitter.com/pT6YmA6qP5

— NHL Public Relations (@PR_NHL) December 22, 2020

One of the frustrating aspects of the old rule were occasions when a player’s skate had just barely left the ice. Having to determine a matter of millimetres between a player’s skate and the ice wasn’t always easy on video replay and it frankly felt ridiculous to overturn a goal based on the toe of a skate blade barely lifted off the ice.

The rule change feels like a good one: no longer will linesmen need to worry about whether a player’s skate is still touching the ice, just whether their back skate is on their own side of the line.

It will also make video reviews easier. determining whether a player’s skate is on his own side of the blue line is comparatively simple compared to whether the skate is touching the ice. All it requires is a camera along the leading edge of the blue line rather than one at ice level that can see if a skate blade is in contact with the ice.

All in all, it seems like a common-sense change that will make things easier for officials and players alike.

Of course, it wouldn’t be the NHL without one more wrinkle, one last thing left ambiguous. See if you can spot the problem in the following sentence:

“If a player's skate has yet to break the ‘plane’ prior to the puck crossing the leading edge, he is deemed to be on-side.”

The NHL is borrowing from football with the phrase “break the plane,” which is a rule that applies to touchdowns. The word “touchdown” originated in rugby, where the ball literally has to touch the ground on the other side of the goal line in order to score a try. In football, however, the ball doesn’t have to touch the ground: it just has to “break the plane,” which means going across an imaginary three-dimensional plane that extends from the front of the goal line up into the air. 

As long as some part of the ball touches that plane, then the ball “breaks the plane” of the goal line and it’s a touchdown.

In this changed offside rule in the NHL, however, we’re talking about a skate. By using the phrase “break the plane,” the NHL is saying that if any part of the skate touches that imaginary plane extending upwards from the leading edge of the blue line, then the player is offside. 

That raises a question: what counts as part of the skate? If the tendon guard or tongue of the skate breaks the plane of the blue line, does that count? Are we talking about just the boot or maybe just the blade?

This may seem like a silly discussion, but it’s an important one. The changed rule even draws a distinction between a skate touching the ice and a skate that is in the air: “either of his skates are in contact with the blue line, or on his own side of the line.”

That suggests there is a difference: if a skate is still touching the ice, it can be partially across the line. If it’s not touching the ice, then it has to be entirely on its own side of the line. Is that really what the NHL intends with this new rule?

The video they released suggests this might not be their intent: in the example of Erik Haula given partway through, the tendon guard of his skate is across the plane of the leading edge of the blue line, and he’s considered onside.

It could be this is just a case of the NHL borrowing language from football that doesn’t actually apply. It’s possible they don’t mean “break the plane” but rather “fully across the plane.” That would mean part of the skate could be across the blue line, but if even a part of the player’s skate is on his own side of the blue line, he’ll still be onside.

But that’s not what the rule says right now.

Maybe the NHL really does mean “break the plane” and that a player will be offside if any part of their trailing skate breaks the plane of the blue line, this doesn’t eliminate issues with the offside rule and offside reviews: it just creates new problems. Not only will it matter if a player’s skate is touching the ice or not, it will also matter if a millimetre of a player’s skate crosses the blue line ahead of the puck.

The NHL needs to clarify the meaning of the rule. Otherwise, there’s potential for confusion.