Milan have Ibrahimovic back in action this weekend, as the 39-year-old returns in shape after having played for Sweden during the international break.
“Milan are not just Ibrahimovic," Ranieri said. “He's a great champion who is making people understand what football is: sacrifice, passion, serious training, great combativeness and a great desire to improve.
“He's an all-round champion and a player who stimulates his teammates and it's logical that when he's not around, the teammates around him want to show that they are learning."
Ranieri added: "I want to see a strong, tenacious, resilient Sampdoria trying to give their best.
"We know how Milan play, they are the team that scored more points than last year, they are a Scudetto contender.
"We know what we must do."