Chelsea have confirmed that central defender Benoit Badiashile will miss an "extended period" of action following an injury picked up in training last week.
Badiashile missed Chelsea's 1-0 defeat against Manchester City at the weekend, and the prognosis is not a positive one for the Blues, as the injury is worse than first feared.
A club statement states that a hamstring issue will keep Badiashile out for the foreseeable future, and it is likely he will miss all of pre-season as well as the start of next season.
"Benoit Badiashile has sustained a hamstring injury which will rule the defender out for an extended period," read the statement on the club's official website.
"The 22-year-old underwent assessment with specialists earlier this week and Benoit will now begin a rehabilitation programme with the club's medical department."
Badiashile has been one of the more positive January signings at Stamford Bridge, nailing down a regular starting spot in defence, despite being left out of their Champions League squad.
The Frenchman also managed to claim his first Chelsea goal in the win at Bournemouth at the start of May, the club's only win in their last 12 matches.
The injury to Badiashile could see Chelsea dip into the transfer market, or opt to keep Levi Colwill at the club after his loan at Brighton & Hove Albion this season.