Manchester United defender Harry Maguire looks set for a spell on the sidelines with a hip injury.
The centre-back missed the 3-1 home derby defeat to Manchester City in the first leg of the Carabao Cup semi-final on Tuesday night.
It was originally thought Maguire's fitness issue was a foot problem sustained in the goalless FA Cup draw at Wolves.
Maguire, who has often captained the team this season, is not expected to feature in Saturday's Premier League match against bottom club Norwich.
It is understood he could be absent for a period of time, though there has been no official confirmation from United on a likely return date for the England international.
Given United's key run of fixtures coming up - which includes a trip to Premier League leaders Liverpool on January 19 - an extended absence for the £80m former Leicester player would represent a significant blow.
When addressing the issue following the defeat by City, United manager Ole Gunnar Solskjaer had been optimistic Maguire would not be out for long.
"We don't know (about Maguire). He's not going to be long term, but I don't think he'll be ready for the weekend, but let's see," Solskjaer said.
Phil Jones, meanwhile, is expected to shake off a bout of cramp to be available against Norwich if needed.
"It's his first 90 minutes for a while (since October) and he came through it," Solskjaer said.