Leicester Tigers centre Manu Tuilagi is likely to be out of action for six weeks with a broken cheekbone.
The injury will rule Tuilagi out of the opening stages of the Heineken Cup campaign, which begins on 12 November.
His fellow centre Anthony Allen is set to be out for a lengthy spell with a thumb injury.
Director of rugby Richard Cockerill confirmed: "Manu suffered a broken cheekbone after a clash of heads in the Gloucester game and we'll be without him for about six weeks.
"Anthony Allen has had an operation on his thumb after an injury in an accident at home.
"We're having a terrible run of luck, especially with Mathew Tait's groin injury and Billy Twelvetrees being out."