Norwich City boss Daniel Farke believes that Timm Klose could be out for the season.
The central defender suffered a knee ligament injury in the Carabao Cup against Crawley Town.
The Premier League side were humbled by the lower division underdogs.
And the result was made worse by the injury to Klose, who was making his first appearance of the season.
"The first report I have got from my medical department is horrible," said Farke to reporters.
"The first diagnosis with Timm is ACL. That would mean he is out until the end of the seassn or best-case, March or April. We hope and we pray it is not this news. It was an unlucky situation. The Crawley lad slipped and bashed into Timm.
"This can happen in these type of games. Timm needed minutes. We had 11 changes and five debuts. When you have this outcome to a key player and his season is nearly over you can only say it is horrible evening.
"With Christoph it was planned to bring him on the pitch for 45 minutes but with the injury to Timm he had to play a little bit longer and got a hit on his back and his hip area. The first news is it is more or less alright. We definitely need him.
"As we wanted to go to the next round my thoughts are with my players as much. We hope for the best in the next days. My biggest concern is not the result but my injured players."
