The Offside Trap

The offside trap is a defensive tactic where defenders step forward simultaneously to leave attackers in offside positions. It is entirely legal but requires precise timing, a defender who steps off the pitch or trips does not count as the last defender.

The full rule

The offside trap involves defenders moving forward as a unit to catch attackers offside at the moment the ball is played. It is a legal tactic. However several specific rules affect how it works: a defender who has gone off the pitch is considered to be on the goal line or touchline for offside purposes, they still count as a defender even though they are off the pitch. This means an attacker cannot benefit from a defender accidentally stepping off the field. Additionally the second-to-last defender determines the offside line, this is usually the last outfield player with the goalkeeper counting as one defender.

Key points

✓Offside trap is completely legal, a standard defensive tactic
✓Defender who steps off pitch is considered on the boundary line for offside
✓Attackers cannot exploit a defender accidentally going off the pitch
✓The goalkeeper always counts as one of the two last defenders
✓Timing must be precise, stepping after the ball is played does not make it offside
✓VAR checks the exact moment the ball is played, not when the defender steps

Scenarios

Scenario 1

Defender steps off pitch as ball is played

Offside

As a through ball is played, a defender accidentally steps off the pitch over the touchline. An attacker appears to be level with the last defender.

Correct call: The defender who stepped off is still counted as being on the touchline for offside purposes. The attacker may still be offside, the defender off the pitch is not ignored.

Common mistake: Ruling the attacker onside because a defender is off the pitch. That defender still counts as being on the boundary line.

Scenario 2

Defenders step forward after the ball is played

Onside

A through ball is played and the defenders step forward a split second after the ball is released.

Correct call: Onside. Offside is judged at the exact moment the ball is played. Defenders stepping after the ball is released does not affect the offside calculation.

Common mistake: Flagging offside because the attacker ends up past the defensive line when they receive the ball. The moment of the pass is what counts.