Middlesbrough central defender Matthew Bates faces another lengthy spell out of action after suffering renewed knee problems.
The 20-year-old sustained damage to the cruciate ligament in his left knee during a pre-season friendly against Darlington on Tuesday, having been making his comeback from a serious injury to his other knee.
Manager Gareth Southgate told the club's official website: "We all feel for Matty, who was looking forward to playing football again after a long period on the sidelines.
"He had applied himself so well to get back in contention and this latest injury is obviously difficult for him to accept.
"He will get the best possible medical support from us as far as treatment and rehabilitation are concerned and we're all right behind him at this difficult time."
Boro's head of medical staff, Grant Downie, added: "It's a devastating blow for a player who was recovering from an injury to his other knee.
"Matty applied himself terrifically well to recover from his initial injury and all our thoughts are with him."
Bates has made 32 appearances for Boro to date, as well as tasting first-team action while on loan at Darlington and Ipswich Town.