Chelsea fear Benoît Badiashile will miss the start of next season after the defender sustained a groin injury in training last week. There were initial hopes the injury was not serious, but further tests have indicated that Badiashile could be out for four months. The injury could require surgery, which would potentially lead to the former Monaco defender missing all of pre-season. Mauricio Pochettino, who is due to be announced as Chelsea’s new manager soon, would have to prepare for his first campaign without one of his key defenders. Chelsea are awaiting the results of tests. If Badiashile is out it would boost Levi Colwill’s chances of breaking into the first team. Colwill has spent the season on loan at Brighton and Chelsea do not want to lose the centre-back. Badiashile, who joined in January, is one of nine Chelsea players who could be missing for Thursday’s game at Manchester United. Chelsea have been overhauling their medical department since Todd Boehly and Clearlake Capital took over the club last summer. The number of changes has been a point of discussion in the dressing room. The long-serving head physiotherapist Thierry Laurent and the medical director Dr Paco Biosca departed earlier this season. Chelsea were missing 10 players when thrashed 4-0 by City in the FA Cup in January.