Why was Timothy Weah ruled offside on first-half World Cup goal?

Timothy Weah thought he had taken the United States one step closer to the knockout stage of the 2022 World Cup in Qatar.

The 22-year-old ran onto Weston McKennie’s sublime pass shortly before the half-time break and confidently poked the ball past the onrushing Iran goalkeeper Alireza Beiranvand into the empty net.

But it wasn’t to be: the goal was disallowed for offside.

Replays of the decision confused some viewers, however. Because it appeared as though Weah was level with the last defender. And the decision appeared to be reached instantaneously.

Why was that the case? We explain below.

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Was Weah offside?

Yes, unfortunately for the USMNT Weah was offside when he ran onto the ball.

Replays clearly showed that Weah’s knee and upper body were offside as they were beyond the last Iran defender, Majid Hosseini.

This close to a 2nd for USA
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The offside law states: “A player is in an offside position if: any part of the head, body or feet is in the opponents’ half (excluding the halfway line) and. any part of the head, body or feet is nearer to the opponents’ goal line than both the ball and the second-last opponent.”

You can score a goal in football with your knee or upper body and so Weah was offside.

But why was the decision so quick?

The decision involved the use of semi-automated offside technology, which is a new feature at the 2022 World Cup.

Regular viewers of the Champions League might be familiar with the technology used to make offside decisions as it was used, with success, throughout the recently-finished group stage. On the vast majority of occasions, the time it took to make the decision was much quicker than it would have been had the VAR officials been forced into offside geometry.

Initially, the on-field assistant referee is tasked with making the decision to raise their flag and signal that a player is in an offside position. However, as we have seen across Europe, they will often wait to signal offside until the period of play has come to an end as an incorrect premature flag could cost a team a goalscoring opportunity.

The semi-automated offside technology comes into operation in the instance when a goal has been scored or a potentially match-defining decision has been made (penalty or red card). It checks whether or not the goalscorer, or any players involved in the build-up, has strayed offside at any stage.

The technology uses 12 tracking cameras underneath the roof of the stadium to track the ball as well as up to 29 data points on each player. Those 29 data points include all limbs and body parts that are relevant for making an offside decision.

An inertial measurement unit will be placed inside the centre of the ball and it will send data to the video operation room 500 times per second which will allow for accurate detection of when the ball has been kicked.

As soon as a player receives the ball in an offside position, the technology provides an automatic alert to the officials in the video operation room. Before informing the on-field referee of the decision, the video match officials must validate the decision by confirming that the kicking point and the automated offside line are correct.

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(Photo: Getty Images)