Wales lock Luke Charteris faces six to eight weeks out of action because of a broken foot.
The 31-year-old, who has won 48 caps for his country, suffered a broken bone in his left foot playing for Racing Metro against Montpellier on Saturday.
Charteris, who left relegated Perpignan at the end of last season, is likely to miss at least six French Top 14 games.
But the 6ft 9in lock could be back for the European Rugby Champions Cup match at home to Northampton on 18 October.
That date of return to action would see Charteris available for Wales' international campaign in the Autumn, which starts on 8 November against Australia at the Millennium Stadium.
Wales then face Fiji, New Zealand and South Africa on successive weekends in Cardiff.