Hull could be without captain Andy Dawson for up to six weeks after the defender sustained a knee injury in training.
The full extent of Dawson's problem will be revealed once the club have received the results of a scan but they fear he could be a long-term absentee.
Tigers' assistant manager Craig Shakespeare told the Hull Daily Mail: "Andy Dawson has picked up an injury in training and he's going for a scan. The early signs are not very good, we're looking at four to six weeks."
He added: "It's terrible news for the boy because he's been terrific since coming back into the team.
"We're gutted for him and for ourselves because it was just an innocuous challenge in training.
"Straight away after he struggled to walk."
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