Chris Sutton has been ruled out of Celtic’s UEFA clash with Barcelona.
Sutton has been suffering form an ankle injury and his absence is a significant blow to the Scottish club who are already without frontman John Hartson through injury.
“It’s a massive blow and we will miss him going into a game like this,” said O’Neill.
“We’re all disappointed and none more so than Chris himself but he’ll have the problem looked at by experts on Friday so we’ll maybe have some more news then.”
Barcelonaare on something of a roll at the moment, winning their last seven games and O’Neill aadmits his side face a stern test in the Nou Camp.
“Eight or nine weeks ago, morale didn’t seem high in their camp but now they are going away from home and winning convincingly so it’s a big ask for us.”
“Barcelona are one of the biggest clubs in the world,” said Celtic midfielder Stilian Petrov.
“But we just want to perform well and go through to the next stage.”
“In normal circumstances it would be a difficult game but the way things have transpired it is even more difficult,” added the Northern Irishman.
“We’re going in with plenty of enthusiasm and determination regardless of who is playing in the side and I would probably take a 0-0 if Chris is due back in a couple of weeks time.”