The 2010 European champions have lost their last two Serie A home games in embarrassing fashion, going down 1-0 to relegation-threatened Novara and then being outplayed 3-0 by strugglers Bologna.
The defeats have led some supporters to call for coach Claudio Ranieri's dismissal despite the former Chelsea, Juventus and AS Roma coach having previously revitalised the club after a dreadful start to the season under Gian Piero Gasperini.
"There is a good team here and the club is healthy and strong," Ranieri told Italian TV.
"He's not a problem but a solution - but at the right time," said Ranieri. "I think an Inter coach is duty-bound to try to integrate players with a special quality.
"I'll have to take some decisions and I will," added the coach who may be glad his ageing team are away in the first leg.
In contrast to Inter's roller-coaster form, Marseille have been models of consistency of late and have not lost in any competition for 15 games stretching back to November's Champions League group stage defeat at home to Olympiakos Piraeus.
The Champions League is one arena where the 1993 winners have not outshone Inter, Didier Deschamps's side scraping through with a last-gasp 3-2 victory at Borussia Dortmund while the Italians advanced as group winners.
France midfielder Alou Diarra, replaced at half-time in the fourth-placed team's 1-1 home Ligue 1 draw against Valenciennes on Saturday after taking a blow on his toe, is expected to be fit.
"He was better on Sunday but we have to wait a little bit. It doesn't seem to be serious so we hope he will be there against Inter," assistant coach Guy Stephan told the club's website.
Marseille: 30-Steve Mandanda; 24-Rod Fanni, 3-Nicolas N'Koulou, 21-Souleymane Diawara, 13-Djimi Traore; 4-Alou Diarra, 12-Charles Kabore, 18-Morgan Amalfitano; 28-Mathieu Valbuena, 9-Branda
