Harlequins centre Paul Sykes is likely to miss the rest of the 2006 season having suffered kidney damage in the win against Hull last Friday.
Sykes, in the old Broncos colours, was Supporters' Player of the Year
Sykes - the longest serving player in the current squad - remains in hospital in Hull while the full extent of the injury is assessed.
At best he will be out of action for two months but the most likely scenario is a season-ending injury.
"Paul's long-term health is our main concern," said Quins coach Tony Rea.
"We're not even thinking at this stage about football. I've been checking regularly that he is responding to treatment and that his spirits are OK."
Sykes was the club's leading points scorer in 2005 and set new club records for points and goals scored in one season, including a perfect 12 from 12 goals against Wakefield at Griffin Park.
"I'm gutted," he said. "I am just going to hope for the best. They are not going to operate so that's something positive. Fingers crossed from here."
Harlequins, buoyed by their first win of the season at Hull, face Castleford in the engage Super League at the Twickenham Stoop on Sunday.