Tommy Bowe has given Ireland a major injury scare ahead of this season's RBS 6 Nations Championship.
The British and Irish Lions Test wing and prolific try-scorer will miss the Ospreys' Heineken Cup clash against Toulon on Saturday, and Ireland coach Declan Kidney must now await news over Bowe's availability for the opening Six Nations appointment with Italy in Rome on February 5.
"We've withdrawn Tommy from this weekend's game on medical grounds, pending further investigation and specialist opinion for a knee problem," said Ospreys physiotherapist Chris Towers.
"Due to the onset of some recent symptoms, we scanned him this week, which highlighted an issue that could potentially develop into something problematic.
"As such, we felt that it is in Tommy's best interest to take these precautions.
"We have notified the Irish medical team, and following further investigations next week we should be able to establish the most appropriate course of treatment for the problem and to confirm whether it will interfere with Tommy's involvement in the Six Nations with Ireland."
Bowe, 26, is rated among the most dangerous wings in European rugby and is a major part of Kidney's Six Nations plans. He has scored 16 tries in 36 appearances for Ireland.