Racing 92's Argentina winger Juan Imhoff is a doubt for the Top 14 play-offs due to a thigh issue, a source close to the French club told AFP on Tuesday.
Imhoff, 33, who has been included in the Pumas squad for July Tests against Wales, suffered the muscular injury which can take up to a month to recover from, in last weekend's win at Agen.
He will be sidelined for this Saturday's home game with Brive, the Parisians' final match of the regular season.
The six-time league winners are third in the table and have already claimed a play-off spot but can clinch a semi-final place if they better the results of leaders La Rochelle and/or second-placed Toulouse this weekend.
Imhoff made his Test return in last November's first win over New Zealand after a five-year international absence due to his decision to play abroad.
Argentina face the Six Nations champions in Cardiff on July 10 as well as a week later, and could play a third match in Europe.