Norwich boss Chris Hughton is hopeful Robert Snodgrass' hospital treatment following the Capital One Cup loss to Manchester United is merely precautionary.
The Scotland international was knocked out in a clash of heads with United's Rafael in the second half and was carried off on a stretcher after around eight minutes of treatment.
Hughton said: "He's gone to a local hospital.
"I think that is very much a precaution, he was out for a period of time. It is very much concussion.
"He has also taken a whack in the incident itself so they will have a look at that and X-ray that just to make sure there is nothing broken.
"But by the time he was on his way out he was awake and aware of what was happening around him."
Snodgrass was injured in the process of forcing a save from United goalkeeper Anders Lindegaard, one of the few chances the visitors created.
Javier Hernandez scored twice as United eased into the quarter-finals with a routine 4-0 win.
The Mexican continued where he left off after scoring Saturday's winner against Stoke, striking from the penalty spot and heading a second on a wet night at Old Trafford.
Phil Jones put the result beyond any doubt with a fine late volley and Fabio came off the bench to net the fourth in injury time.
Hughton had made eight changes - one fewer than United boss David Moyes - and that appeared to have an effect on his side's intensity.
Despite that, the Canaries boss felt United were be fortunate to be awarded the 20th-minute penalty from which Hernandez struck first.
Adnan Januzaj, whose emergence continued with another sparkling display, went down on the slippery surface after contact from Leroy Fer.
Hughton said: "Could our performance have been better? Yes, we could have been better on the ball.
"But we were given a penalty against us which was incredibly soft and not a penalty.
"To have a penalty given against us, in that fashion, as soft as that, really gives Man United a lift and deflates you.
"But they scored good goals, they have got great quality and they are clinical in everything they do."
United have now gone six games unbeaten after a difficult start to the season and assistant boss Steve Round feels momentum is building.
He said: "This club is used to winning, it has a winning mentality.
"There were no great celebrations after the win on Saturday and none tonight. We just move on to Fulham, that is how it is.
"You need to go on runs in this league and this club is the best in the business at building that."