What is semi-automated offside technology?
Semi-automated offside technology (SAOT) uses tracking data to help officials establish player positions and the relevant ball-touch moment. It speeds up part of the analysis, but trained match officials still validate the information and apply the offside law.
The word “semi” matters. A system identifying a player’s coordinates is not the same thing as making every decision about whether that player committed an offside offence.
How player and ball tracking work
FIFA’s modern SAOT uses dedicated stadium cameras to capture the position of players and the ball multiple times per second. The system follows relevant body points, including those used to assess offside. Where connected-ball data is available, a sensor inside the ball can help identify the precise moment of contact.
Optical tracking and ball-touch data are combined to produce candidate offside information. The technology aims to reduce the manual steps that previously involved selecting frames and drawing virtual lines.
Implementations differ by competition. Not every league uses identical camera configurations or a ball containing a sensor, so an explanation of one tournament’s hardware should not be applied universally.
What happens after an automated alert?
In a typical semi-automated workflow, the system flags a possible positional offside to the video officials. They validate the selected kick point, player identities and offside line before advising the referee. Advanced systems can additionally send a fast audio alert directly to on-field officials for certain clear positional offsides.
This still leaves legal questions that tracking alone cannot resolve. A player can be in an offside position without committing an offence. Officials must consider interference with an opponent, active involvement and whether the ball was deliberately played or deflected by a defender.
For the broader distinction between factual evidence and judgment, see the clear-and-obvious-error principle.
What do the 3D animations show?
Broadcasters may display a computer-generated scene with players and an offside line. These visuals help explain the positional findings, using tracked data rather than a single ordinary television frame.
They should not be mistaken for a complete reconstruction of every subjective football decision. The animation can communicate player position; the question of whether a player interfered with an opponent can require human interpretation and additional match footage.
Does the technology eliminate all offside controversy?
No. SAOT can improve consistency in positional measurement and reduce the time needed to assemble evidence. It cannot make the definition of active involvement irrelevant, settle every deliberate-play question, or guarantee that all implementation challenges disappear.
Technology may also have fallback procedures if a component is unavailable. These can include established video review tools. Compare this specialised positional system with goal-line technology, which answers a narrower yes/no question about the whole ball crossing the goal line.
Frequently asked questions
Is semi-automated offside the same as VAR?
No. It is a support technology that can be used within VAR workflows.
Does every SAOT system need a sensor in the ball?
No. FIFA’s descriptions allow optical tracking, with connected-ball data where available.
Can an onside player still be penalised by mistake?
Match officials still need to check the data and apply the law. Technology supports the judgment; it is not a promise of infallibility.
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These sources explain the rules or technologies in their official context. Check competition-specific procedures where appropriate.