Lacazette picked up a thigh injury in the 2-0 win over Metz last month, forcing him to miss the 0-0 draw at Monaco, a stalemate that allowed Marseille and PSG to pull within two points of Hubert Fournier's side at the top of the table.
And the France forward - who has netted 25 goals in all competitions this season - is expected to again be on the sidelines as Lyon welcome a PSG side gathering momentum ahead of their trip to the Stade de Gerland.
"It's a very important victory," he told PSG's official website.
"We played as if it was the final. I am very happy to be heading home with a ticket to the Stade de France. February is going to be a crucial month for us and we know it."
Viewed as one of Argentina's most exciting young players, Marseille will hope that Ocampos can develop under the tutelage of compatriot Marcelo Bielsa as they seek a first French title since 2010.
Caen are still only a point above the bottom three going into Saturday's game with Toulouse, and coach Patrice Garande is wary that their luck could soon turn.
"I don't mean to say that I am not pleased, but I think it is good to take a little step back from it all," Garande said. "Things can change quickly, but I am happy with the state of mind my players have shown."
Elsewhere, strugglers Metz and Evian face Bastia and Bordeaux respectively, while Montpellier host Lille, Reims take on Lorient and Nantes visit a Nice side that saw Hatem Ben Arfa leave after the Ligue de Football Professional ruled him ineligible to play for them this season.
