All Blacks legend Dan Carter is facing a race against time to be fit for Perpignan's crucial Heineken Cup clash with the Ospreys on Saturday.
The 26-year-old limped out of the French side's 40-14 home win over Bourgoin in the Top 14 at half-time after aggravating an old Achilles injury. He is now set to undergo further tests on the problem.
"The pain was getting worse after about half an hour of the match and as a precaution I came off at half-time," Carter told AFP.
"It was frustrating because I really wanted to play and the team had a really good match. I'll get tests on Monday and will decide with the staff if it would be better to take several days off from training."
The game against the Ospreys will be vital to both side's hopes of qualifying for the quarter-finals. The Ospreys, who beat Perpignan 15-9 at the Liberty Stadium in Round 2 before Carter had joined the club, are level at the top of the Pool 3 table on 15 points with Leicester Tigers, with the French side trailing in third with nine.
To stand any chance of qualifying for the last eight Perpignan must gain a bonus point victory from their final two games and hope other results go their way.
The Ospreys, who qualified for the quarter-finals for the first time last season, know they must take something from the game at Stade Aime Giral to set up a sixth round win-at-all-costs game with the Tigers in Swansea.
Perpignan's victory kept them in third place behind leaders Toulouse and Stade Francais in the Top 14. Meanwhile, the Ospreys lost top spot in the Magners League with a 25-21 home defeat at the hands of Munster on Friday night.
Nearly 40 players were involved in the first Wales Under 18 training session of the season. WRU National Performance Manager Gethin Watts is excited at the potential shown by the group and expects the Regional Under 18 Championship to hone their skills even further.