Bayern Munich forward Mandzukic missed his country's defeat to Brazil in their Group A opener last Thursday after being sent off in the second leg of their qualification play-off victory over Iceland.
However, he has now served his ban, meaning coach Niko Kovac will be able to unleash him in Croatia's crucial clash with Cameroon - who were beaten 1-0 by Mexico in their first game.
And Pranjic, who also missed out against Brazil due to injury, believes his team will be better off with Mandzukic leading the line.
"He (Mandzukic) definitely makes us stronger and you can't replace him like-for-like," the 32-year-old told FIFA.com. "He's prepared to go out and die for the cause.
"Lajic (Nikica Jelavic) did really well against Brazil but Mario is Mario.
"We need him. We're a totally different team without him."
