Both sides are in desperate need of all three points to keep pace with Group B's leaders.
Arsenal and Schalke look like the clear class of Group B and heavy favorites to advance to the knockout round of the Champions League, but both Montpellier and Olympiakos have a chance to turn around their campaigns on Wednesday. If either side can grab all three points, they'll be back in the running for a place in the round of 16.
Montpellier pulled off a surprising comeback draw against Schalke in their last game, but were poor in the first half of that match. They're also coming off two straight losses in Ligue 1 and appear to be closer to relegation than European places. Olympiakos have looked good domestically, but with two losses already in Champions League, their prospects of making the knockout stage won't look good if they fail to beat Montpellier.
Montpellier injuries and suspensions
Out: Karim Ait-Fana (knee), Garry Bocaly (suspended).
Olympiakos injuries and suspensions
Out: Ariel Ibagaza (groin), Tassos Papazoglou (shoulder), Dimitris Siovas (thigh), Giannis Fetfatzidis (knee).
Ait-Fana's knee injury is a massive blow to Montpellier's hopes, both to win this match and to qualify for European football next season. He's out for six months with ligament damage. John Utaka is back from injury while Geoffrey Jourdren and Marco Estrada were rested over the weekend. Romain Pitau returns as well after serving a suspension.
Olympiakos are without four player who did not travel to France. Vasilis Torosidis and Kostas Mitroglou were rested this weekend and should play.
Match Date/Time: 8:45 p.m. local, 2:45 p.m. ET
Venue: Stade de la Mosson, Montpellier, France
TV: DirecTV Soccer (U.S.), Sky Sports Events Centre (U.K.), NET Sport (Greece), beIN Sport (France).
Online: FOX Soccer 2 Go (U.S.), Sportsnet World Online (Canada)