"Keane is the expression of the club on the pitch. He is Alex Ferguson on the pitch," Ranieri said on Friday after a training session before Sunday's premier league showdown between the two championship pretenders.
Defender Terry and midfielder Lampard have been Chelsea's most regular outfield players in a team renowned for its mutability as Ranieri seeks his ideal combination from a talented and highly paid squad of internationals.
"John Terry or Frank Lampard could represent Chelsea like Keane does for Manchester. They are young, they are strong men and they have character," the Italian coach said.
One point separates Chelsea in second from third-placed champions Manchester United in the league. Arsenal are top, a single point in front, with the rest of the teams well adrift.
Ranieri insisted, however, there was still a gap of pedigree and experience between his side and the champions.
"Chelsea were born only this season," Ranieri said, referring to the influx of top players following billionaire Russian Roman Abramovich's takeover last July.
"Manchester United have been used to playing at the top level in England and Europe for years. On Sunday we will be happy to see how big the gap is. We are working hard to close it."
Chelsea, who will be without former United player Juan Sebastian Veron because of injury, have an unenviable record against United at home, having won only twice since the premier league started in 1992.
But they have demonstrated a new strength of will this season, grinding out results when playing less well and producing occasional fireworks, such as this month's 4-0 thrashing of Lazio in Rome in the Champions League.
Both United and Chelsea qualified for the knockout stage of the Champions League, albeit with less than sparkling midweek performances, and Ranieri was in relaxed and jovial mood on Friday despite Sunday's challenge.
His tenure at Stamford Bridge has long been the subject of speculation, particularly after England boss Sven Goran Erkisson was photographed meeting Abramovich a few months ago.
But Ranieri said he would love the chance to mould a team as Ferguson has done since 1986 at United.
"Three years aren't enough. It would be fantastic to work here 17 years like Alex Ferguson," he said.
