Guinness Premiership leaders Bristol have suffered a major blow with the loss of their former England hooker Mark Regan for up to six weeks.
Regan, who played pivotal roles in the opening league wins against Bath and Newcastle, broke his thumb during the Newcastle Falcons clash and has undergone surgery.
"Mark has had it operated on and the surgery went well, so we are looking at maybe six weeks for him, aiming at the European games against Narbonne and Northampton (in late October)," said Bristol physiotherapist Paul Tompkins.
"It is a blow, and he is understandably gutted with the team going so well."
Regan, a member of England's World Cup-winning squad, is set to miss Premiership appointments with Gloucester, London Irish and Saracens, plus Powergen Cup clashes against Bath and Gloucester.
England flanker James Haskell insists he will be pushing as hard as possible to be back from a toe injury in time to make his case for a spot in Eddie Jones' side looking to defend their RBS 6 Nations title next year.