The 19-year-old suffered the injury in his first training session with his new team-mates following his switch from Motherwell and will now target a return to action for pre-season ahead of the 2020/21 campaign.
“James will not play again this season unfortunately,” McCann told the media after last night’s draw with Swansea City.
“He’s going to need an operation. We’re gutted for the boy because he’s only just come to the football club.
“We’ve got the reports back after seeing the specialist and he’s going to need an operation just to tidy (his ankle) up a little bit. It’s a gutting one for us all.
“He’ll be back for pre-season and it’ll be like having the new player he is again.”
However, there was some positive news on the injury front with McCann also revealing that Eric Lichaj and Herbie Kane don’t require surgery on their recent ankle ligament injuries and could yet return to action before the end of the season.
“On Eric and Herbie, they don’t need operations,” said McCann. “Hopefully both of them could be back before the end of the season but I don’t know in terms of the timescale.”