England flanker Chris Robshaw could be a doubt for the Six Nations because of a shoulder injury he suffered against Worcester.
Robshaw star has been ruled out of Saturday's game with Sale, and Harlequins have revealed that the former England skipper is facing either "an extended period of rest and rehabilitation, or an operation."
He will see a shoulder specialist early next week to decide the best way forward, who was outstanding in England's back-row in 2016.
The Six Nations - in which England are the defending champions after winning the Grand Slam last year - begins next month. England kick off their campaign against France on February 4.
The loss of Robshaw would be a big blow to England coach Eddie Jones. He has become a hugely reliable blindside, doing much of the unseen dirty work in the rucks and mauls.
England have a number of injury problems in the pack ahead of their title defence.
Saracens prop Mako Vunipola is already a doubt for the Six Nations with suspected knee ligament damage, as is his brother, No 8 Billy Vunipola, who also has a knee injury.
Saracens lock George Kruis is also a doubt because of cheekbone damage but fellow second row Joe Launchbury should be back in action in time for the France opener following his calf injury, which is not as serious as first thought.
One timely piece of good news for England is the return to action of James Haskell, who has been named on the Wasps bench this weekend. He has been out of action since England's summer tour of Australia with a toe injury.