O'Neill laments Larsson loss
The Swedish marksman suffered a double fracture of his cheekbone during the 2-1 win over Livingston on Sunday.
The clash with Gustave Bahoken resulted in the striker being taken to hospital and following surgery it has been confirmed he will miss at least the next six weeks of the season.
Larsson had plates and screws inserted in the fracture, and will spend Monday evening in hospital before being allowed home.
He will then return to hospital on Saturday, for the surgeon to assess the injury, but it is believed he will miss the next six weeks.
A downcast O`Neill said: "Sometimes these operations go well, and I'm only guessing but I'm hoping that it is going to be weeks rather than months.
"It's a major blow to us because he is a world-class player.
"However, Henrik has come back from a broken leg and will want to return quickly."
Celtic are chasing Rangers at the head of the SPL table, but Larsson will play no part in the league clash with their Glasgow rivals on March 8 or the CIS Cup final a week later.
Compatriot Magnus Hedman knows how much The Bhoys will miss the prolific marksman telling Sportbladet: "He will really be missed but we have got to try and cope without Henke (Larsson) for a while.
"We all know how much he means for the club. A player who scores 34 goals is a big blow."