St Etienne have suffered a blow prior to their crunch Ligue 1 derby at Grenoble with the news midfielder Blaise Matuidi will be out for a month with a thigh injury.

The 21-year-old, who has held Les Verts' midfield together at times this season, picked up the injury in the 1-0 UEFA Cup defeat at Werder Bremen on Thursday.

With Mouhamadou Dabo (ankle), Cedric Varrault (thigh), Geoffrey Dernis (adductors) and Dimitri Payet (knee) also doubts, ASSE coach Alain Perrin has some selection headaches, although he can recall players rested for the Bremen match.

They include Araujo Ilan, Sylvain Monsoreau and David Gigliotti, while Stathis Tavlaridis is back from suspension.

"Our training sessions have above all been focused on recuperation and against Grenoble, we could benefit from a little fresh blood, using players who have been rested," said Perrin.

Lyon are St Etienne's chief rivals in the Alpine region although Sunday's match still holds importance to Perrin.

He added: "We must remember the home match when Grenoble won at the Stade Geoffroy-Guichard (2-0). We must get revenge."

St Etienne's 2-1 win over Nantes last weekend lifted them out of the relegation zone and three points clear of trouble.

They are three points adrift of their opponents, whose 2-1 win against Caen last time out has also given them some breathing space while extending their unbeaten run to five matches.

The promoted club have been primarily content with keeping it tight at the back of late, and they are proving hard to break down.

Milivoje Vitakic plays his last match before a three-game ban and Sofiane Feghouli is still nursing a knee injury.