Wimbledon gets under way today with line judges scrapped for the first time in the tournament's 148-year history - replaced by AI-powered technology. Some of the sport's biggest stars have descended on south-west London for the showpiece two-week event at the All England Club - including defending singles champions Carlos Alcaraz and Barbora Krejčíková. Britain's hopes rest on Jack Draper, Katie Boulter, Cameron Norrie and Emma Raducanu, who will battle through back injury in an attempt to win her second career Grand Slam. And all eyes are on how this year's occasion copes with a shift in the way the game is umpired, as human line judges are replaced by artificial intelligence systems instead. The controversial decision has left fans torn, with some praising the forward-thinking idea while others disliking the idea of technology taking the place of a person.

The moment tennis fans have been waiting for is nearly here – the start of Wimbledon 2025. From Monday, some of the biggest stars will battle for the most prestigious prize in tennis, including defending champions Carlos Alcaraz and Barbora Krejčíková. Britain's hopes rest on Jack Draper, Katie Boulter, Cameron Norrie and Emma Raducanu, who will battle through back injury in an attempt to win her second career Grand Slam. Novak Djokovic aims to win his eighth Wimbledon men's single's title, matching the record set by Roger Federer, but Australian fan favourite Nick Kyrgios will be absent. This year, Wimbledon will do away with human line judges for the first time in its 148-year history, to be replaced with AI.

If there's one thing baseball fans are averse to, it's change. Over the MLB's 149-year history, alterations to the game's rules, like lowering the pitcher's mound (1968) or introducing instant replay challenges (2014) came only after years of heated debate between reformers and purists. Maybe the most contentious issue ever to divide these two camps is whether or not to replace notoriously inaccurate human home plate umpires with less fallible machines. Though that was once largely considered out of the bounds of possibility, MLB games officiated by so-called "robot umpires" are now closer to reality than ever before. Starting this week, batters stepping up to the plate during spring training games will have the ability to challenge an umpire's pitch calls and have them immediately reviewed by a computer.

The Hawk-Eye computer vision system made its tennis debut in 2003 for broadcasting purposes, but was approved in 2005 after a notorious U.S. Open Tennis match between Serena Williams and Jennifer Capriati in 2004, during which Williams was the victim of multiple bad calls in the third set and went on to lose the match. Use of Hawk-Eye was expanded during the COVID-19 pandemic, and the 2020 U.S. Open was played without line judges on all but two of the main courts. Since Hawk-Eye has been in use, between 190 and 200 judges have been replaced, depending on the stage of the tournament, says Sean Carey, managing director of competition operations, at the U.S. Tennis Association (USTA). "The reason we bring technology in for this level of tournament--and we want to do it across every level if we could afford it--is to ensure integrity and the fairest and most even calls,'' Carey said. Hawk-Eye, which uses cameras to track the trajectory of a ball and create a three-dimensional (3D) representation of it, is now being used by 23 of the top 25 global sports leagues and federations, according to the company. Yet, the sentiment appears to be that AI will never fully replace human judges. This has been the subject of much debate in Major League Baseball (MLB), a sport grounded in tradition, noted Daniel Martin, an associate professor of economics at the University of California at Santa Barbara. MLB is using Hawk-Eye to automatically monitor strike zones, and is questioning whether to get rid of umpires, given that the system is "incredibly accurate,'' he said.

Last month, Mark Clattenburg, who is generally regarded as one of the finest referees in professional soccer, left England's Premier League for a better-paying position in Saudi Arabia. Plenty of famous players have chosen riches over prestige and joined less established leagues in Asia and the Middle East. But this was one of the first times that a referee of Clattenburg's stature and prominence had left in his prime. Just last year, he was selected to referee two of the most important matches on Earth: the finals of the Champions League, in May, and then the European Championship, two months later--plum gigs that testified to his skill. To commemorate the occasion, he had the feat tattooed on his arm--a testament to his knack for preening.

Players suffer complete meltdowns as they hurl insults. Postmatch beers can undo some of the damage, but the shame and resentment linger for days. More civilized times may lie ahead. French inventor Grégoire Gentil has designed a $200 GoPro-size device that can be fastened to any net post and detect whether balls are in or out with surprising accuracy. It's called, reasonably enough, the In/Out.