Derby County defender Jake Rooney has been ruled out for a "significant period" after suffering anterior cruciate ligament damage to his right knee.
He was hurt early on in Derby's defeat at Bolton on Saturday.
The 20-year-old, who is the cousin of former Rams boss and England and Manchester United captain Wayne Rooney, has made 21 appearance for the Rams.
"It's heart-breaking news for Jake," said Rams boss Paul Warne.
"It's tough being a young professional when you're trying to make your way in the game and to have this sort of injury is hugely disappointing.
"We are gutted for him, but he's got our full support and we'll do everything we can to help him get back in the best possible condition."
Rooney, who joined the Rams in August 2022 after coming through the academy at Burnley, signed a new three-year deal with the League One side in July.
The defender's absence adds to the Rams' injury woes, with midfielder Max Bird and wing-backs Kane Wilson and Joe Ward each sidelined since mid-August.