The Foxes have managed only seven points from their opening six games, and following the 4-1 defeat to Manchester United on the weekend, defender Danny Simpson revealed that the players are struggling to adjust to the new set-piece rules which prohibit pulling and blocking in the box.
However, Ranieri has imposed his charges to overcome that mindset and get back to what they know best - playing football.
"Yes, we concede a lot of goals," Ranieri said at his Champions League press conference ahead of the home game against Porto on Tuesday.
"I spoke to the players yesterday and they were scared. What the referees speak about is not a new rule, it's something we're used to doing. I said why change?
"Last season we were one of best in league and conceded very few goals from the set pieces and now we leave four metres. Now I can't jump?
"We have to go back to our strengths."