Middlesbrough boss Aitor Karanka has confirmed that defender Alex Baptiste has a suspected broken leg.
The injury took place in Boro's pre-season win over York City when the 29-year-old challenged for the ball but came off second best in the tackle.
Baptiste was stretchered from the field, and his manager is fearful of the worst after seeing the severity of the injury.
Karanka told the Northern Echo: "This is the kind of day where I don't want to speak about football. We are all very disappointed, and after Alex was injured, I left the game.
"Sometimes, it's difficult for me to understand how unfair football is. One week ago, I was together with Alex in my office. Now, he is in the hospital. If the feeling from Wembley is a motivation, then we have another motivation now to dedicate it to him.
"I don't know exactly what has happened, but it is going to be a serious injury and he will be out for a long time. I think it is a complete break, although we will have to wait and see."
Baptiste joined Boro from Blackburn Rovers earlier this month.