Those who are new to the sport of ice hockey may be wondering why there are several coloured lines painted on the ice. These are to section off the playing surface into separate attacking/defending zones and a neutral zone. The blue lines are essential for the on-ice officials when it comes to calling a play either onside or offside.
What is Offside in Hockey?
In simple terms, a player is ruled to be immediately offside if he enters the opposing team’s blue line before the puck does if his team is in possession of the puck or has passed it into the opposing zone. A player may be legally inside the opponent’s zone before the puck however, as long as the puck enters the zone from an opposing player.
The NHL Offside Rule Explained
It may sound simple enough but the NHL offside rule has several aspects to it.
Offside is covered by rule 83 in the NHL rule book and it states that the position of the attacking player’s skates will be used to determine if he’s offside or not rather than the position of his stick. If both skates are completely over the opposing blue line before the puck has entered the zone then he’s deemed to be offside.
However, the player is onside if one of his skates is on his own side of the blue line or in contact with the line at the moment the puck completely crosses over the leading edge of the blue line.
The rule states that the blue line is also defined by an imaginary ‘plane’ which rises upwards from the ice where the blue line is situated. Therefore if a player’s skate is off of the ice but above the blue line, the skate is considered to be on the line. If the player’s skate is above the ice but has broken the plane onto the other side of the blue line before the puck enters the zone then it’s considered to be offside.
Crossing the Blue Line
If a player is in control of the puck and crosses the blue line before the puck does then he’s considered to be onside. This often occurs when a player takes control of the puck and skates backwards across the line while in possession of it.
Also, if a player passes, carries or plays the puck back into his own defensive zone while an opponent is still inside the blue line then the opponent is onside as it was the team in possession of the puck which passed or carried it back into its own zone.
Deflections and Bounces
If a defending player propels the puck outside of his own defensive zone and it deflects or bounces off of a teammate and back into the zone then there is no offside if an opponent is still in the zone.
However if an opposing player causes a bounce or deflection in the neutral zone off of a member of the puck-carrying team by a stick or body check, a delayed offside will be signalled by the official.
Any puck that deflects or bounces off of an on-ice official who is in the the neutral zone and goes back into the defending zone will result in any attacking players inside the blue line to be ruled offside.
If the puck-carrying team clears its own blue line and the puck deflects or bounces off of an opponent in the neutral zone and back inside the blue line then any player inside the blue line is offside.
In addition, If the attacking team propels the puck into the opponent’s defending zone and it deflects or bounces off of any player from either team, an offside is called if a player from the attacking team enters the blue line first.
Delayed Offside Rule
To make matters even more complex, there is also a delayed offside which means the linesman won’t immediately blow the whistle and call the play dead when a player is ruled to be in an offside position.
In this scenario, one or more attacking players have entered the opposing team’s defensive zone before the puck has crossed the blue line but the defending team has possession of the puck. The play will be allowed to continue, enabling the team to carry or pass the puck out of its own zone without being impeded.
If an opposing player interferes with the puck carrier before the puck has left the defending zone then the play will be whistled dead for offside. Once all of the attacking opponents have left the defending zone by coming back outside of the blue line they are then allowed to re-enter the zone as the linesman will signify that the delayed offside has been nullified.
In short, if the linesman is signifying an impending delayed offside call, the play will be whistled dead if an attacking player touches the puck while it’s still in the opponent’s defensive zone or attempts to play the puck or forces a puck carrier to retreat further into his own zone.
Player Changes During Delayed Offside
If a player change is made on the fly while a delayed offside is being signified, any player who enters the ice surface from his own bench which is inside of the opponent’s blue line must clear the zone or will be offside.
Delayed Offside and Scoring
If an attacking player shoots the puck into the opponent’s defending zone while one or more teammates are already inside the zone it will result in a delayed offside and play will continue if the defending team gains possession of the puck.
However, if the puck enters the net in any manner during this delayed offside situation, it will be ruled no goal even if the attackers have cleared the zone before the puck enters the net.
The only time an attacking team may score a goal during a delayed offside is if the defending team puts the puck into its own net without any interference from the attackers.
Intentional Offside Rule
The NHL also recognizes a play which is regarded to be an intentional offside. This is when the attacking team propels the puck into the opponent’s defensive zone while one or more of its players are already inside the zone. This is done deliberately for any reason as a way to have the play whistled dead.
If a team is ruled to have committed a deliberate offside they will be penalized by having the ensuing faceoff take place in their own zone.
An intentional offside is also called when an attacker deliberately touches or plays the puck to stop the play during a delayed offside situation.
Did the NHL Offside Rule Change?
The modern offside rule was altered slightly in 2020/21 as a player could still be in an onside position if one of his skates was in the air and hovering over the blue line when the puck crossed it and entered the attacking zone.
The previous version of the rule stated that one of the player’s skates had to be on the ice either on the blue line or on his own side of the line.
Please watch the video explanation and example of this current offside rule:
NHL Offside Rule Examples:
Here is a video of some of the NHL’s most controversial missed offside calls:
Here is one that was a huge controversial goal in the playoffs, the Colorado Avalanche vs the Edmonton Oilers. Cale Makar takes the puck in when teammate Valeri Nichushkin was still on the opponents side of the blue line. They claimed Makar didn’t have possession of the puck. Check it out:
Why is the Offside Rule Important in Hockey?
The offside rule was originally created to prevent teams from ‘goal hanging’ which means attacking players would set up shop near their opponent’s net while the puck was in the neutral zone or their defensive zone.
The offside rule means players must now wait until the puck has fully entered the zone before they can go after it.
What Happens When a Player is Offside?
When an attacking player is ruled to be offside the linesman will blow the whistle to stop play. If a delayed offside is ruled, the play will continue to allow the defending team the opportunity to clear or carry the puck out of its own end unimpeded.
If an attacking player interferes with the defending team while it has possession of the puck in its own end the linesman will blow the whistle as the delayed offside is now ruled to be offside.
Where is the Faceoff After an Offside Whistle?
If the play is ruled offside when an attacker carries the puck over the blue line the faceoff will take place outside of the blue line in the neutral zone, on the dot closest to where the puck carrier was.
If an offside is called due to an errant pass or when an attacker shoots the puck into the defending zone, the faceoff takes place in the zone where the shot or pass originated from.
If a delayed offside is called, the faceoff also takes place at the nearest dot in the the neutral zone, but in the case of an intentional offside the faceoff comes back into the offending team’s defensive zone.
How Does a Player Avoid Being Offside?
A player can avoid being ruled offside simply by making sure the puck fully precedes him across the blue line before he enters the opponent’s zone.
In the case of a delayed offside, the player must make sure he has left the opponent’s zone and the linesman has nullified the delayed offside before crossing the blue line and re-entering the zone.
Can Teams Challenge Offside Calls in the NHL?
Since the 2015/16 season NHL teams have been allowed to challenge an offside ruling only when it results in a goal against them. During the final minute of play in regulation time and during overtime periods, the NHL Situation Room reviews any scenario which could lead to a coach’s challenge, including a possible offside leading to a goal.
This means no coaching challenge is needed at these times since the league will automatically review every goal.
When a coach does want to challenge a missed offside call which resulted in a goal he must let the referee know before the puck is dropped at centre ice to resume play.
When the challenge has been initiated the on-ice officials will review the play on a video screen while in contact with the NHL Situation Room. Several camera angles are used to determine if the play was offside or not and the final decision is then announced to the crowd inside the arena.
If the play was deemed to be offside after the video review, the original on-ice onside call is overturned, the goal is waved off and the playing clock is re-set to the time of the missed offside call.
When a team initiates a coaching challenge for a missed offside call and the challenge is unsuccessful, the team making the challenge will be assessed a two-minute minor penalty for delay of game.
If a team is unsuccessful in one or more challenges during the same game a double minor penalty will be assessed for delay of game. A missed offside challenge can only be made if the puck doesn’t leave the defending zone again prior to the goal being scored. Once the puck leaves the zone, any potential missed offside call previous to it isn’t allowed to be challenged.
What’s the Difference Between Offside and Icing?
Offside and icing are two different and unrelated hockey infractions. Offside occurs when an offensive player enters the opponent’s defensive zone by crossing the blue line before the puck does whereas icing occurs when a team shoots or passes the puck from its own side of the centre-ice red line and it goes untouched into the opposing zone and crosses the goal line.
Read our related post all about the NHL Icing Rule here.
Was Offside Always a Part of the Game?
In the early days of ice hockey, forward passing wasn’t allowed and this meant the puck had to be skated up the ice. Forward passing was allowed in the neutral zone in starting in 1918/19 and in 1927 forward passing became legal the defensive and neutral zones.
In 1929 forward passing was then allowed in all three zones of the ice surface. Passing in all zones led to a dramatic increase in goals per game and it was here to stay.
But at the same time, players were allowed to receive a pass from a teammate while situated anywhere on the ice. This enabled players to camp out in the opponent’s defensive zone and receive a pass all the way from their own defensive zone.
To battle against goal-hanging, the NHL then introduced an offside rule in 1929, shortly after allowing forward passing in all zones and teams had to carry the puck over both the defensive and offensive blue lines.
The NHL didn’t introduce the centre-ice red line until 1943/44 and the introduction of the new line saw a new rule implemented which allowed players to pass the puck out of their own defensive zone to teammates who were on their own side of the red line. The NHL then did away with the centre-ice red line for offside purposes in 2005.
What’s the 2-Line Pass Rule
The two-line pass rule existed in the NHL when the centre-ice line was in effect. The rule stated that a player’s pass to a teammate must not cross two lines. This meant a pass couldn’t be made from a team’s defensive zone across its own blue line and across the red centre-ice line.
It also meant you couldn’t pass to a teammate from the neutral zone across the centre-ice line and the opposing team’s blue line. If the puck crossed any two of these lines while being passed to a teammate the play was ruled offside.
Is it Still a Rule?
The two-line pass disappeared when the centre-ice line was no longer used for offside purposes in 2005. Players may now legally make an onside pass from anywhere in their defensive zone all the way to the opposing team’s blue line.
Final Thoughts
The modern offside rules have been around for several years now as the NHL decided to do away with the centre-ice red line for offside passes in 2005, but the newest offside rule change came about in 2020/21.
Still, with the sport of ice hockey being so fast it’s almost impossible for NHL linesmen to get every call correct. There are dozens of coach’s challenges each season due to missed offside calls that resulted in goals and almost all of these are successful.
This means linesmen are possibly missing several offside calls in each game but it’s only apparent when a coach’s challenge is made. This could lead to future tinkering with the current rules so don’t be surprised if some type of technology is introduced in the future to help linesmen make the correct call as often as possible.
This could perhaps be something similar to the goal line technology used in soccer and the technology used in tennis to determine if the ball was inside or outside of the boundary lines.
We have many NHL rule guides that you can read here.
Jamie is the founder of Hockey Response and he is the chief writer/ lead editor. Jamie has been playing hockey for over 20 years. He was the defenseman of the year in NL and has played Jr A level hockey. Jamie has coached several kids hockey camps and he was the assistant coach of the Western Kings.
