Greg Rusedski has branded it “insanity” that betting firms have installed Carlos Alcaraz as favourite to win the 2026 US Open, given the Spaniard has been sidelined for more than four months with a right wrist injury.The former world No 4 cast serious doubt over Alcaraz’s decision to stage his comeback at a Grand Slam, describing it as “not the smartest thing” on his Off Court With Greg Rusedski podcast.Alcaraz, 23, confirmed last week that he intends to return at Flushing Meadows after his last competitive outing came in a first-round victory at the Barcelona Open back in April. The seven-time major winner missed both the French Open and Wimbledon during his lengthy spell on the sidelines.Carlos Alcaraz is set to return to tennis for the first time since April | GETTYDespite the prolonged absence, bookmakers currently have Alcaraz priced at 2/1 to lift the trophy.Before any decision on the men’s singles draw is made, Alcaraz will first partner tennis legend Serena Williams in the mixed doubles, with their opening match scheduled for Tuesday. The main draw singles competition does not get under way until Sunday.Rusedski suggested this pairing will effectively function as a trial run for the Spaniard’s injured wrist. The 1997 US Open finalist indicated he would still be taken aback if Alcaraz ultimately enters the singles competition.”I think he’ll make a decision [on playing singles] after the mixed doubles event,” Rusedski said. He added that the Williams partnership also carries a commercial dimension, noting that Alcaraz and the American icon share the same clothing brand sponsor, making it “huge publicity in the week.”Carlos Alcaraz is also set to team up with Serena Williams during mixed doubles | GETTYRusedski acknowledged that arriving in New York early offers Alcaraz the chance to hit with elite opposition during practice. “He’ll be able to practise with top world-class players every single practice session,” the 52-year-old said, citing the likes of Alexander Zverev and Novak Djokovic as potential sparring partners.However, he stressed that training sessions cannot replicate the demands of Grand Slam tennis. “He won’t be practising in a manner for three out of five sets. So, this is so many question marks up in the air,” Rusedski cautioned.The central concern remains whether the wrist can withstand the rigours of best-of-five-set matches.”I’m still questioning, is that wrist ready for three out of five sets?” he said. “I hope I’m wrong because it’s great to have him back.”Alcaraz boasts a formidable record at Flushing Meadows, having claimed US Open titles in 2022 and 2025. Across his career in New York, he has accumulated 24 victories against just three defeats, translating to a win rate of nearly 90 per cent.Carlos Alcaraz is the reigning champion at the US Open after beating Jannik Sinner in last year’s final | REUTERSHis status as reigning champion partly explains why the odds remain so heavily in his favour. According to Oddschecker, Alcaraz sits at 2/1, well clear of 2026 French Open champion Alexander Zverev at 15/4.Novak Djokovic, chasing a record-extending 25th Grand Slam title, is available at 8/1.One notable absence from the draw is world No 1 Jannik Sinner, who confirmed his withdrawal from the tournament through injury, removing another potential obstacle from Alcaraz’s path should he decide to compete.