The Europa League is Lazio's target and the Rome side are bidding to respond from Sunday's draw against AC Milan.
Lazio boss Edy Reja said on corrieredellosport.it: "We have several injuries, I hope to recover some.
"Klose will not be there. He will train tomorrow afternoon, then on Thursday he will try to return to the group.
"I'll have to talk to Postiga. He could start, then we'll check his condition during the game.
"He has important qualities and can give us a big hand. I expect an important contribution.
"(Stefano) Mauri can also play as the false centre forward, I will decide tomorrow who to select."
Lazio have won their last two away games - at Fiorentina and Cagliari - but Reja expects a challenging evening.
"Genoa play with great intensity," he said.
"It is up to us to put them in trouble."
Genoa boss Gian Piero Gasperini anticipates a test for the hosts.
"Lazio are chasing the opportunity to reach Europe," he said.
"For us it will be an important test to see improvements.
"Lazio are dangerous on the counter-attack and produce good goals. Both teams will fight for the victory."
Genoa are without former Lazio midfielder Matuzalem due to injury.
"We have a little difficulty with many absences in the same area," Gasperini added.
"The lack of Matuzalem will be a good opportunity for youngsters to show off."