Saints star Calum Clark will undergo surgery on a shoulder injury on Wednesday, throwing his participation in England’s Six Nations campaign into doubt.
The flanker suffered the injury during the first half of Northampton’s 27-20 Heineken Cup defeat at Glasgow on Saturday, being withdrawn after 37 minutes.
He left the ground with his arm in a sling and it has been confirmed he has damaged his AC joint.
It means he will now need an operation and will be in rehab at the club for the foreseeable future.
Clark had been named in England’s 32-man EPS squad for the Six Nations, which starts on February 2, but Worcester’s Matt Kvesic has been called up as cover.
The Saints man tweeted about the injury on Tuesday afternoon, saying: “My shoulder needs an operation so I will be out of action for the foreseeable future. That’s the game.”
England boss Stuart Lancaster said: “It is a shame for Calum as he had worked hard to get back into the senior squad. But these things happen and our medics will work closely with Northampton on his rehab.”