"It was on Sunday afternoon that it felt sore. He has had some scans, we think there is something there, and the specialist is looking at him now. I couldn't tell you at the minute, but I'd say he is looking doubtful for the game. How long he might be out, I'm not sure."
Laursen's injury raises interesting questions about who might captain the side on Friday. Gareth Barry, who was stripped of the captaincy in the summer, would be a contender, as would Curtis Davies who led the side on Uefa Cup duty in Prague, and Brad Friedel.
Meanwhile, O'Neill said that he expected Cuellar, who picked up a knock against West Ham, to resume training this week, but suggested that he remained a doubt for the Arsenal game.
O'Neill said: "Carlos is feeling much better. I'm hoping that he might train tomorrow, but he is getting better every day."