Why semi-automated offside technology will be used and how it works ahead of Sunderland vs Sheffield United

There will be a notable addition to this month’s Championship play-off final between Sunderland and Sheffield United at Wembley, the use of semi-automated offside technology (SAOT) for the first time in the competition.

The Black Cats face the Blades in the capital on Saturday, May 24, with a place in the Premier League at stake. While the stakes are high on the pitch, fans of both clubs should also be aware of a key technological change that could impact proceedings.

A year ago, Premier League clubs voted unanimously to implement SAOT, with plans to introduce it during one of the three international breaks last autumn. However, after those initial deadlines passed, further testing was required. The technology finally made its debut during the FA Cup fifth round tie between Aston Villa and Cardiff City on February 28.

It was then trialled again in three of the four FA Cup quarter-finals. Following successful tests, the Premier League confirmed on April 1 that SAOT would be officially adopted in its competition from April 12. Now, ahead of the Championship showpiece, the EFL has confirmed that the system will also be in place for the Sunderland vs Sheffield United final at Wembley.

What is SAOT — and why is it being introduced?

According to the Premier League, SAOT will not change the accuracy of offside decisions, which it says has already been 100% this season. Instead, its main advantage is speed. The system is expected to cut down the time taken for offside checks, saving an average of 31 seconds per incident.

Unlike the current VAR process, match officials will no longer need to manually draw offside lines — except in rare "edge cases" where players obstruct the cameras’ view of key actions. One such delay was seen during the Bournemouth vs Wolves FA Cup tie on March 1, where the system struggled with visual obstructions.

The images generated by SAOT will be available to broadcasters and displayed on stadium big screens. A red line will indicate an offside decision, while a green line will indicate an onside call. A white vertical "wall" will represent the offside line itself, with a blue “pulse” marking the defender’s relevant body part. If an attacker is offside, the offending body part will be shown breaking through the wall in red.

Up to 30 cameras have been installed in each Premier League stadium to support the technology, capturing footage at 100 frames per second. These cameras track the ball and up to 10,000 “mesh” data points on each player’s body. This allows the system to assess offside positions with pinpoint accuracy, automatically flagging potential offsides to the VAR and SAOT operators. This same technology will now be used at Wembley for the Championship play-off final.

Why is it still only semi-automated?

Despite its precision, SAOT doesn’t remove the human element entirely. VAR officials still have to confirm that the system has correctly identified the “kick point” — the exact moment the ball was played — as well as the relevant player and body part. They also continue to rule on subjective elements, such as whether an offside player was interfering with play or whether a defender’s touch was a deliberate action.

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So while SAOT promises faster decisions, the final say still lies with the officials. What’s clear, however, is that the 2024 Championship play-off final will be one of the most technologically advanced matches ever played in the EFL — and fans of Sunderland and Sheffield United will be watching every angle.

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