Norwich striker Grant Holt has a suspected hamstring problem after hobbling off the pitch during the his team's 2-1 win over Wigan on Saturday.
The striker has scored four Premier League goals and started every game this season, helping his side reach seventh place under new manager Chris Hughton.
"Yes, we're worried. You're worried about any injury," the ex-Newcastle boss told the BBC.
"We don't know much yet. He's felt his hamstring slightly. We don't think it's a big one but we won't know until the next couple of days.
"It's a concern - and a bad time - but it's not right to speak about it in bad terms when we don't really know.
"Hopefully he'll be OK. If not, the competition within the side continues."
In Holt's absence it may be left to in-form players Anthony Pilkington and Wes Hoolahan to provide the goals if Norwich are to continue their recent good run of form.
Pilkington, who scored the first and assisted Hoolahan for the second goal against Wigan, spoke fondly of his team-mate, who recently signed a new contract.
"He's a great player. He's probably the best player I've played with," Pilkington said.
"You see his foot work and how good he is on the ball. It's great that he's here for the next three years - it's great for him and great for the club."