Harlequins and England skipper Rob Purdham is seeking a second opinion on the back problem that looks like ruling him out for the rest of the season.
The versatile Cumbrian, 27, has missed the club's last three matches after getting injured in training.
He is hoping the injury is not a serious as first thought but Quins are not holding out too much hope.
Prop forward Daniel Heckenberg is also out for the season after being told he needs a shoulder reconstruction.
There are also doubts over the future of former Kangaroos tourist Richard Villasanti.
He arrived on a two-year deal in February after having a minor operation to cure a long-standing knee problem but is now set to leave the club without playing a game.
The club say they plan to issue a statement on the former Cronulla forward later this week.
Quins have reacted to the loss of Purdham, who was being tipped for Great Britain call-up, by signing second-row forward Stephen Bannister from St Helens.
Forward Joe Mbu and winger Rikki Sheriffe have also been reunited with the London club after short spells with stricken National League One side Doncaster Lakers.
Meanwhile, Harlequins winger Jon Wells will not face further action following his sending-off against Wigan last week.
Wells was found guilty of careless use of the forearm at a Rugby Football League disciplinary hearing on Tuesday but his red card was deemed sufficient punishment.
Wells was dismissed for a high tackle on Darrell Goulding in the 25-6 Carnegie Challenge Cup defeat at the JJB Stadium on Friday.