Blanc admitted that fringe players Christophe Jallet, Zoumana Camara and Hervin Ongenda are all missing but said that Cavani would feature for the first time since pulling up with a thigh injury in the 2-0 win against Bordeaux on 31 January.
"He has worked really well this week," Blanc said of Cavani, who has scored 20 goals this season since moving to France from Napoli for a Ligue 1 record fee of €64m last summer.
"As long as there are no problems in the last session (on Saturday) he will be in the squad. Will he start? You will see."
Traditionally the biggest game in the French calendar, 'Le Classique' has lost a bit of its lustre recently with Monaco emerging as the biggest threat to PSG's domination of Ligue 1.
Marseille are 18 points behind their enemies from the capital coming into the game at the Parc des Princes, although they have boosted their chances of UEFA Champions League qualification thanks to a five-match unbeaten run.
"This is a special match. It always will be in my opinion and we know the reasons for that," Blanc said, who spent two seasons as a player at Marseille and scored the winner for OM in this fixture in 1997.
"But for there to be a bit of spice to it, both clubs need to be doing well. If there is less pressure, it's maybe because you (the press) are creating less.
"There is always this rivalry between the two clubs, between the south and the north, the capital and the province."
PSG won 2-1 away to Marseille in the reverse fixture in October, despite having Thiago Motta sent off half an hour in and going a goal down.
Since then, though, OM have sacked Elie Baup and replaced him with sporting director Jose Anigo until the end of the season.
"They are solid. The reverse fixture was one of our best matches, with ten against 11 for almost an hour," admitted Blanc.
"Paris were very, very strong. We will play our own game. Will they take risks or will they sit back? I don't know. Everyone knows how we will play."