Middlesbrough midfielder Kevin Thomson has been ruled out for two months after fracturing his fibula against Leicester City.
The Scotland international was making just his second appearance for Boro on Saturday when he was hurt in the second half of the 0-0 draw.
He will not require surgery on the injury, but has been denied the chance to establish himself in the Boro team following his arrival from Rangers.
Boro manager Gordon Strachan rued the setback for Thomson, which follows on from the serious injury suffered by Willo Flood in the opening game against Ipswich Town.
Strachan told the club's official website: "I was hoping Kevin would be all right, but you can tell when someone's seriously hurt.
"It's bad news for the player and a big loss too for the team because he has been our best passer in the first two league games.
"That's two stretchers in two weeks because we lost Willo Flood long-term last week too. We've got Rhys Williams missing too of course. We've not had much luck with injuries in my time here."