Norwich midfielder Alex Pritchard will be out of action for up to three months because of a pre-season ankle injury.
The 24-year-old was injured in a friendly against Cambridge United in mid-July and it was thought he would be sidelined for six weeks.
But boss Daniel Farke has now confirmed that the former Tottenham youngster requires surgery.
"There's bad news for Alex Pritchard. We will have to do without him for at least 12 weeks," he said.
"Pritch is a key player for us, but we have to handle it and we'll deal with it."
There is some good news for Farke, however, with forward Steven Naismith available for Sunday's Championship game against Sunderland after completing a ban.
The 30-year-old was sent off against Leeds in the penultimate game of last season and the suspension was carried over into the new campaign.
Meanwhile, midfielder Ben Godfrey, 19, has signed a new four-year contract with the club.
He has made six first-team appearances so far, scoring once in a 6-1 EFL Cup win over Coventry 12 months ago.