Arsenal defender Laurent Koscielny could miss this summer’s World Cup after a suffering an Achilles injury during the Europa League semi-final second leg at Atletico Madrid.
The 32-year-old lost his footing off the ball and was in obvious distress as he clutched his lower leg.
The injury forced the Gunners into a change after just 12 minutes, with Calum Chambers coming on.
France international Koscielny has been nursing an Achilles problem all season.
“It doesn’t look very good,” said Wenger. “You can always hope that the scan will say something different but the first signs aren’t very good.
“It looks like it could be ruptured although I’m a bit cautious – no-one can say that clinically at the moment.”
Asked about Koscielny’s chances of recovering in time for the World Cup, Wenger said: “That depends on the scan. If he has ruptured it the chances are non-existent.”
Achilles injuries usually mean at least six months out.
Arsenal have three games remaining in the Premier League, starting with a home match against Burnley on Sunday, followed by away games at Leicester and Huddersfield.
France have been drawn alongside Australia, Peru and Denmark in Group C for the World Cup finals, which get under way on 14 June.