Racing Metro 92 have suffered a huge blow ahead of the opening round of Amlin Challenge Cup fixtures.
The Parisian-based outfit will be making their European debut having been promoted as champions of the Pro Division 2 last season.
They face a daunting start when they travel to former Heineken Cup winners London Wasps in round one, before hosting fellow French side Bayonne in round two.
And they will be without star back row forward Sébastien Chabal for both those fixtures after the former Sale Sharks player picked up a knee injury at the weekend.
The France international stayed on the ground after a 68th-minute scrum in the 17-12 win over Montauban and was forced off to be replaced by Jonu Qovu.
After further medical investigation that revealed a twist in his anterior cruciate ligament, Chabal is expected to be out of action for a minimum of two weeks.
There was further bad news for Pierre Berbizier's squad as ex-All Black fly-half Andrew Mehrtens injured his sternum in the same fixture and is also a doubt for Sunday's opener at Wasps.