The teenage right-back was hurt in a tackle in the 41st minute and was carried off on a stretcher after lengthy treatment.
The highly-rated prospect looks set for several months on the sidelines. Boss Phil Brown said: "Conor has fractured his fibula and dislocated his ankle as well and it is the dislocation that is the complicating factor.
"It's a real disappointment because he is a good kid and a player who is at the beginning of his career and this is a setback.
"He'll got to the hospital in Manchester and probably get a pot on it for about six weeks and he'll be out for a while now."
Source: PA
