In February last year, Arsenal were denied victory against Brentford due to a costly video assistant referee (VAR) error. The Premier League intends to change its VAR track record by inking a new contract with a company called Genius Sports, which will bring together the power of iPhone and machine learning models to help game officials make an offside call.

The new system can apparently spot a player’s position on the field before calling an offside with better accuracy.

Set to roll out later in the 2024-25 season, the semi-automated offside technology (SAOT) — powered by AI and data platform GeniusIQ — is expected to mitigate issues with delays and human process errors.

Genius Sports and its subsidiary Second Spectrum are known for optical tracking and data-based work in NBA basketball. The proprietary Genius Sports computer vision system will be installed in every Premier League stadium.

In 2016, The International Football Association Board (IFAB), which oversees the laws of the game, approved trials for video referees and about two years later, the Premier League clubs voted to introduce VAR in the 2019-20 season. Fifa, the global governing body, started officially using machine learning-powered limb-tracking tech and embedded ball sensors in 2022; the software could track 29 points of players’ bodies.

With the new technology, at least 28 iPhones (mostly iPhone 15 Pros and newer, when they launch) will be deployed at every stadium in the Premier League.
The iPhones will be housed in waterproof cases (mounts can hold up to four iPhones fitted together) that come with cooling fans and are connected to a power source.

The system can be scaled up to fit the needs of the game. It may result in a system that can track 7,000 to 10,000 points on each player in any game. More data points can help in recording muscle mass and skeletal frame differences that can be analysed for precise offside calls.

Broadcast video typically captures football moments at 50 or 60 frames per second while the smartphone-based system — internally known as Dragon — can capture
up to 200 frames per second (the system will initially record at 100fps), reducing gaps between frames. Helping the system will be a machine intelligence system to contextualise movements in real time.

Originating in 1863, the offside rule is meant to deter players from lurking near the opposition goal to look for scoring opportunities. Older SAOS systems used
between 10 and 15 cameras. iPhones today are powerful and, at the same, cheaper than many camera options. Cost may not be a deterrent for the Premier League but they need a system that can easily be scaled up.

Since VAR has been up against criticism several times, football fans could be wary of a new technology.

Tony Scholes, Premier League chief football officer, said: “We are confident that by using the newest and most accurate technology available we will see the time taken for offside decisions reduced significantly alongside a consistent application of the offside lines.”