Rise of the Robot Officials: From Hawk-Eye to AI Refereeing
- Shane Riddle
- 1 day ago
- 10 min read
The referee's whistle is one of sport's oldest sounds and increasingly, it's being joined by a synthetic voice calling "out." Over two decades, officiating technology has travelled from settling fans' arguments in the TV studio to actually making the call on the field. In this article we'll trace that journey from Hawk-Eye to FIFA's semi-automated offside and baseball's incoming robot umpires, taking in the swimming pool and the goalposts of Aussie Rules along the way and crucially, where the human still holds the whistle.
Key Takeaways:
It started with cricket, not tennis: Hawk-Eye was invented by British mathematician Paul Hawkins around 2001 and first used to enhance cricket TV broadcasts before officials ever trusted it.
From "challenge" to "call": Tennis has crossed a line with Wimbledon scrapping human line judges in 2025 for the first time in 147 years, joining the Australian and US Opens.
Football kept a human in the loop: FIFA's semi-automated offside technology proposes a decision in seconds, but a video official validates it and the referee confirms it.
Baseball is next: MLB's Automated Ball-Strike challenge system arrives for the 2026 regular season, letting players challenge a call rather than handing every pitch to a machine.
It has spread to the pool and the ball itself: Hawk-Eye now helps officials judge swimming turns and finishes (now in use at venues including South Australia's SAALC), while the AFLW uses a sensor-filled "smart ball" to flag scores in real time.
The trade-off is trust: When a machine errs, there's often no visible explanation — and fans value decisions they can understand as much as decisions that are correct.
Table of Contents
Officiating Tech Quick Facts:
Hawk-Eye was invented by Paul Hawkins and launched around 2001, first used in cricket broadcasting.
It made its tennis Grand Slam debut at the 2006 US Open as a player-challenge system.
Wimbledon 2025 removed line judges for the first time in 147 years.
FIFA's semi-automated offside debuted at the 2022 World Cup, using 12 cameras tracking 29 points per player at 50 frames per second, plus a sensor in the ball reporting 500 times a second.
MLB's Automated Ball-Strike challenge system was approved in September 2025 for the 2026 season.
Hawk-Eye's swimming video-review system helped officiate at the 2024 Paris Olympics; the AFLW has used a sensor "smart ball" since 2024, and the AFL scaled back its ARC score reviews in 2026.
Sources: Pi in the Sky / Hawk-Eye history, FIFA, MLB, Swimming Victoria, ESPN, AFL
How Hawk-Eye Started It All
Almost every modern officiating system traces back to one idea. Hawk-Eye was invented by Paul Hawkins, a British mathematician and former club cricketer and developed at Roke Manor Research, launching around 2001. Tellingly, it wasn't built to officiate at all, it was a broadcast tool designed to let cricket viewers see whether a ball would have hit the stumps. The seed it planted, as one tennis historian put it, was the realisation that there were other ways to judge a ball than the human eye.
The system uses a network of high-speed cameras to triangulate a ball's position many times a second and reconstruct its trajectory in 3D. From cricket it spread to tennis, then to football's goal-line technology, and Sony acquired it in 2011. What began as a way to win an argument in the pub became the backbone of officiating across more than 20 sports.
Tennis: From Challenge to Full Automation
Tennis shows the full arc of the journey better than any other sport. After a contested 2004 US Open match involving Serena Williams, the International Tennis Federation re-examined how line calls were made, and Hawk-Eye made its Grand Slam debut at the 2006 US Open, but only as a challenge system. Players got a limited number of reviews while the human line judges still made the calls.
The leap from "challenge" to "call" came with Hawk-Eye Live, which makes automated calls in real time with recorded voices. The US Open dropped most line judges in 2020, the Australian Open became the first Grand Slam to play entirely without them in 2021, and the US Open followed in 2022. Then, in 2025, Wimbledon retired its line judges for the first time in 147 years, replacing some 300 of them with an electronic system supported by around 80 on-court assistants. That leaves the French Open as the lone Grand Slam holdout, where the chair umpire still climbs down to inspect the ball's mark in the clay, a method Hawkins himself argues is actually less accurate than the cameras, though he concedes that if everyone accepts the mark, "it is still fair."
It hasn't been flawless. At Wimbledon 2025, a system error in one match meant a clearly out ball went uncalled and a point had to be replayed, a reminder that "automated" is not the same as "infallible."
Football's Semi-Automated Offside
Football took a more cautious route, and the language matters, it's semi-automated. After VAR's debut at the 2018 World Cup, FIFA introduced semi-automated offside technology (SAOT) at the 2022 World Cup in Qatar. The setup is genuinely impressive consisting of 12 dedicated tracking cameras under the stadium roof follow up to 29 data points on each player's body 50 times a second, while a sensor inside the match ball reports its position 500 times a second to pinpoint the exact moment of the kick.
But the system doesn't make the final decision. It generates an automated alert to the video officials, who then validate the proposed kick point and offside line before informing the on-field referee, who confirms it. The payoff is speed and consistency. FIFA's head of refereeing, Pierluigi Collina, said trials cut offside decision time from around 70 seconds to roughly 20. For the 2026 World Cup, FIFA has signaled further refinements to the system, though the precise specifications are best treated as evolving rather than fixed.
Baseball's Robot Umpires
The newest frontier is the strike zone — and baseball's approach is a clever compromise. After years of testing in the minor leagues since 2019 and across 2025 spring training, MLB's Joint Competition Committee approved the Automated Ball-Strike (ABS) challenge system in September 2025 for the 2026 regular season.
Notably, MLB tested two models: one where the machine called every pitch, and one where the human umpire keeps calling but players can challenge. The league chose the second. The human plate umpire still calls balls and strikes; each team gets two challenges per game, retained if successful, and only the pitcher, catcher or batter can call for one — by tapping their cap or helmet, with no help from the dugout. The Hawk-Eye-powered system then shows the verdict on the videoboard within seconds. The case for it is striking: MLB noted that around 61.5% of player, manager and coach ejections in a recent season were related to balls and strikes, even though umpires already call roughly 94% of pitches correctly. In 2025 spring-training trials, about 2.6% of pitches were challenged and just over half were overturned.
Hawk-Eye Dives Into the Pool
Officiating technology isn't only for the pitch and the court — it has gone into the water, and it's no longer experimental. Swimming Victoria partnered with Hawk-Eye to launch what they billed as the world's first Swimming Video Review Technology back in 2022, and its technical officials have used the system to officiate as video Inspectors of Turns since the start of the 2025 long-course season. The system — Hawk-Eye's SMART (Synchronised Multi Angle Replay Technology) — gives officials synchronised overhead and underwater views of every lane, so they can adjudicate turns, strokes and finishes with far more certainty than the naked eye allows. It was also used to help officiate at the 2024 Paris Olympics and Paralympics, and World Aquatics now publishes formal guidelines for video judging that define the Video Review Judge and Video Review Supervisor roles.
In South Australia, Swimming SA has brought the same Hawk-Eye system to the SA Aquatic & Leisure Centre (SAALC), where it is now used to help officiate competition. The motivation is strikingly practical with some meets needing around 50 technical officials to run, and the system eases that load by handling parts of officiating such as monitoring turns and finishes with underwater cameras added for an even clearer view. It's worth being precise about what "automated" means here, this is video review with experienced officials making the calls from a synchronised, multi-angle vantage point, not a system that issues disqualifications on its own. In a sport that leans so heavily on volunteers, that's a meaningful, working improvement and a clear signal of where pool-deck officiating is heading.
Aussie Rules and the Smart Ball
Australian Rules football offers the most instructive twist of all — because in 2026 the AFL has been pulling technology back as much as pushing it forward. For score decisions, the league has long used video review through the AFL Review Centre (ARC), where a video goal umpire checks synchronised multi-angle footage. When the AFL first trialed Hawk-Eye for goal reviews, it stressed this wasn't tennis-style ball-tracking, it simply gave the umpire better control over synchronised replays.
But after a run of contentious calls early in the 2026 season, AFL football boss Greg Swann announced that the ARC would scale back its role: it would still review every goal, but would no longer intervene in other scoring decisions unless the goal umpire specifically asked for a review. Swann's reasoning could stand as a summary of this whole article, that some reviews were taking too long and frustrating fans, and that there's a balance to strike between getting a call right and protecting "the fabric and the flow of the game." It's a rare, telling example of a governing body deciding that less automatic intervention is the better answer.
On the sensor side, the AFLW introduced "Score Assist" smart-ball technology (built by Sportable) in 2024 with wireless sensors in the Sherrin (ball), track the ball's motion, position, speed, spin and hang time and alert officials in real time if the ball hits a post, is touched in flight, or crosses the goal line. It's a genuine example of sensor-in-the-ball officiating but an honestly imperfect one. The AFL has conceded the system wrongly overturned a goal in a 2024 AFLW match (blaming human error in how the footage was reviewed), and as of 2026 the men's competition still hasn't adopted it, citing the need for further development.
Looking ahead, the AFL is trialling optical, camera-based tracking — reportedly a Vello Technologies system using cameras in the goalposts and around the ground (no chip in the ball) to give goal umpires a real-time call. Swann confirmed in 2026 that optical tracking and camera upgrades are among the things being tested. For now that's firmly in development and, taken with the ARC pullback, a sign the AFL is weighing not just whether technology can make the call, but how much of the game it should be allowed to interrupt.
Six Sports, Six Approaches
Sport | System | Who makes the final call? | Maturity |
Tennis | Hawk-Eye Live (ELC) | The machine, automated "out" calls | Shipping (3 of 4 Slams) |
Football | Semi-automated offside | Machine proposes, official validates, referee confirms | Shipping at major tournaments |
Baseball | ABS challenge system | Human umpire, with player-initiated machine review | Launching for 2026 |
Cricket | Decision Review System | On-field umpire, with player review | Long-established |
Swimming | Hawk-Eye SMART video review | Video officials (Inspectors of Turns) | In use (Paris 2024; Australian state meets) |
Aussie Rules | ARC video review + AFLW smart ball | Video/goal umpire, with sensor alerts | In use; ARC scaled back in 2026; optical tracking trialled |
The Human Cost and the Trust Question
There's a genuine tension worth sitting with being that accuracy is not the same as legitimacy. When a human line judge made a mistake, it was visible and open to appeal; when a machine fails silently, fans can be left confused and frustrated with no route to redress. There's a human cost, too demonstrated by Wimbledon's 300 line judges were part of the championship's fabric and a loss of the theatre that made line calls part of the sport's folklore.
That's exactly why the most thoughtful designs keep a person in the loop. Football's referee still confirms, baseball's umpire still calls, swimming's video officials still adjudicate the turn. The trend is not "remove the human" so much as "give the human a faster, more accurate second opinion." Even Aussie Rules' smart ball only alerts an official, it doesn't blow the whistle itself. And in 2026 the AFL went a step further, deliberately reducing how often its review centre steps into a decision which is a reminder that the direction of travel isn't always "more technology."
Final Thoughts
The rise of the robot official is one of sport's most visible technological shifts, you can see and hear it from your sofa. At its best, it does something quietly democratic, it makes the call the same for everyone, every time, regardless of which end of the pitch you're watching from. And as the move into swimming and Aussie Rules shows, its reach is widening fast with sometimes to relieve overstretched volunteer officials, sometimes to settle a millimetre-fine goal-line call. But the smartest governing bodies have learned that fans don't only want correct decisions, they want decisions they can understand and trust. The future that's emerging isn't a sport without referees, it's one where technology and human judgement share the whistle.
Frequently Asked Questions
Q: What's the difference between VAR and semi-automated offside?
A: VAR is a team of video officials reviewing decisions on screens. Semi-automated offside is a specific tool within that system that automatically calculates the offside line and alerts the officials, who still validate it before the referee confirms.
Q: Do tennis players still get to challenge calls?
A: At tournaments using full electronic line calling, the challenge system has largely disappeared, the automated call is final, so there's nothing to challenge. The French Open, which still uses human line judges, is the main exception among the Slams.
Q: Will MLB's robot umpire call every pitch?
A: No. For 2026, MLB chose the challenge model, the human umpire calls every pitch and players can challenge a small number of calls per game for an automated review. A "call everything" version was tested in the minors but not adopted for the majors.
Q: Is Hawk-Eye used in swimming?
A: Yes. Hawk-Eye's SMART video-review system gives officials synchronised overhead and underwater views to judge turns, strokes and finishes, and it helped officiate at the 2024 Paris Olympics. In Australia it's in use at state level including Swimming SA at the SA Aquatic & Leisure Centre (SAALC), easing the heavy reliance on volunteer officials.
Q: What is Australian Rules football doing with technology?
A: The AFL reviews goals through the AFL Review Centre (ARC) using synchronised video, though in 2026 it scaled back the ARC's role so it no longer intervenes in most scoring decisions unless the goal umpire asks. The AFLW (but not yet the men's competition) uses a "smart ball" with embedded sensors that alerts officials when the ball hits a post, is touched, or crosses the line, and the league is trialing camera-based optical tracking for the future.
Q: Is the technology ever wrong?
A: Yes. Ball-tracking is extremely accurate but not perfect, and systems can also suffer operational errors — as a high-profile glitch at Wimbledon 2025 showed. The accuracy is high; the claim of infallibility is not.
Q: Why doesn't the French Open use electronic line calling?
A: Clay courts leave a visible ball mark, so chair umpires can physically inspect where the ball landed. The French Open has treated that as sufficient, making it the last Grand Slam to retain human line judges.
