The Clermont Auvergne outside half badly twisted his left ankle when one of his own players fell on him in a tackle after 60 minutes of their 9-0 French Championship defeat at Biarritz. The Clermont medical team described the injury as a double twist that caused lateral damage. Jones is expected to be out for between three and four weeks.
With the might of the southern hemisphere due to descend on the Millennium Stadium in November to test Mike Ruddock's Grand Slammers to the full, the Welsh coach is having to face the fact that a number of his Grand Slam-winning squad will be unavailable with injury. Already ruled out of the games against New Zealand, Fiji, South Africa and Australia are Lions prop Gethin Jenkins and centre Gavin Henson, while wing Shane Williams and No. 8 Ryan Jones are also considered highly doubtful.
Jenkins, Henson and Williams have all undergone operations since returning from the Lions tour in the summer, while another Lion, Tom Shanklin, has yet to return to action after resting his injured knee. Also on the sidelines are one of the players Ruddock capped in the summer, Blues hooker Rhys Thomas, while the veteran front row man Robin McBryde has retired.
Jones was a key player in Wales's march to their first Grand Slam in 27 years last season and is the highest points scorer in the French Championship this season.
A special video package as Pontypridd claimed the double for the first time in their history by winning the Principality Premiership final, including match build-up, highlights, post match reaction and dressing room celebrations.