Shrewsbury centre-back Shane Cansdell-Sherriff has been ruled out for at least a month with suspected ligament damage to his shoulder.
The Australian was forced off after 78 minutes of Saturday's 2-1 victory over leaders Southend following an aerial tussle with striker Liam Dickinson which left him unconscious.
Cansdell-Sherriff was taken straight to hospital and later released, but faces a lengthy lay-off.
Manager Graham Turner told the club's official website: "The best case scenario is four to six weeks.
"He's got a nice shiner, a bit of a lump on the side of his head and he took a bit of a battering.
"He came in on Monday and he's due to see a specialist, so we'll see what the outcome of those visits are.
"At the moment it looks likely he won't need surgery, but the chances are it will be four to six weeks."