Notman said: "It's not good news because I'm going to have to have an operation.
"I've rested my ankle totally for the past two weeks but it still feels the same as if I've trained on it. It's not settled and is still swollen.
"I'm obviously very disappointed because I had figured in every game up to the Ipswich one and now it looks like I will not be back until after Christmas.
"I want to get the operation done as soon as possible so that hopefully I could be back for the New Year."