Hull City will be without winger Robbie Brady for up to six weeks after he suffered a calf injury during training.
The news will come as a blow to the club, with Brady playing an important squad role in his 19 appearances this season.
Hull boss Steve Bruce confirmed he was a fitness doubt on Monday after the 23-year-old fell down a hole in a training session.
Speaking on Monday, Bruce said: “Unfortunately Brady has fallen down a hole in the training ground and it looks an awful injury, I have to say.
“We won’t know the extent of it until he has had scans. After seeing him on Friday I doubt he will be available for weeks. It could be the rest of the season.”
Brady missed his side’s 1-0 defeat to Stoke on Saturday after picking the injury up at the end of last week.
The Republic of Ireland international might return before the end of the season but he will miss the club’s next two games against Sunderland and Leicester City.
He will also miss the fixtures against Chelsea, Swansea and Southampton but Bruce will be hoping he can return to help the battle to stay in the Premier League.
Bruce’s side take on Sunderland on Tuesday night at the KC Stadium and they could recall strikers Dame N’Doye and Nikica Jelavic.
N’Doye was rested at the weekend while Jelavic is expected to play a part after recovering from a swollen knee.
The Tigers are 2.17 to beat Gus Poyet’s men, with the draw 3.20 with Dafabet, while Sunderland are available at odds of 3.61.