Dorian West says Saints lock James Craig will need surgery after dislocating his shoulder in the win against Gloucester last weekend.
Craig was forced off during the second half of the 33-6 LV= Cup success and he now looks set for a lengthy spell on the sidelines.
It is the latest in a long line of injury blows for the 25-year-old, who played just 64 minutes for Saints last season due to persistent knee and shoulder problems.
And he is now set to have an operation before starting out on the road to recovery once more.
Saints forwards coach West said: “James has got a dislocated shoulder so he’ll no doubt be having an operation on that.
“We’ll see how long it takes him to get back in the frame.”