Slimani has scored five goals in the last three games against Porto, who are nicknamed the Dragons, including a goal in his final match for Sporting Lisbon last month before his club record £29m move to Leicester on transfer deadline day.
The 28-year-old made his Leicester debut in their opening Champions League Group G tussle, a 3-0 win against Club Brugge, while Ranieri has admitted to tapping into Slimani’s knowledge of Porto as he plots their downfall.
“He’s a goalscorer and has scored a lot of goals against Porto and I’m sure he’ll be a threat to them,” said Ranieri. “Slimani scores so many times against Porto I am thinking if he’s going to play or not.
“I spoke with him about Porto. We have a lot of respect for Porto, they are a more experienced team in Europe than us.
“They have played so many matches in the Champions League and are used to staying at the top of their league and have won six titles in the last 10 years. We respect them a lot but we also try to win. Both teams want to win.”
Goalkeeper Kasper Schmeichel could return to the starting line-up at the expense of Ron-Robert Zieler after missing Leicester’s last three matches with a groin injury, although midfielder Papy Mendy remains sidelined with an ankle problem.
Leicester currently top Group G after their mauling of Club Brugge and Porto’s 1-1 draw with FC Copenhagen.