Former England prop Andrew Sheridan could be forced to retire due to a neck injury, according to reports in France.
The 34-year-old, who has 40 caps for his country, sustained the injury playing for Toulon against Perpignan in Round 12 of the Top 14.
Speaking to RMC, Toulon boss Bernard Laporte expressed his concern over Sheridan's playing future.
"Andrew is out for a month and possibly forever," said Laporte.
"He has always had a problem between his neck and his shoulder. The surgeon has told him that it's not necessary to have a new operation.
"He will now have a month of complete rest and if the pain doesn't go away, then he will have to stop playing rugby."
Sheridan joined Toulon from Sale Sharks in 2012 and won two caps for the British and Irish Lions on the tour of South Africa in 2009.