Top goalscorer Tom Hopper will miss the rest of the season after rupturing his ACL.
Hopper has scored seven goals in 14 games for Blues since joining in the summer.
He suffered the injury in last week’s 3-0 win over Walsall, the same game that Harry Lennon fractured his leg.
And scan results have revealed the true extent of the injury which will mean the striker will now spend nine months on the sidelines.
Hopper will soon undergo surgery on his knee, and everyone at the club wishes Tom a full and speedy recovery.
Blues boss Chris Powell said: “It’s a devastating blow for him first of all and for us as a team and a club because of the brilliant impression he has made so far.
“He’s a natural goalscorer at this level and we’ll miss him but first and foremost we want him to get back healthy and fit and that’s the most important thing.”