The 21-year-old joined the Premier League champions from Everton last week, and could make his debut as the defending champions kick-off their campaign at home to new boys Southampton on Sunday.
But Rodwell acknowledged that the depth of talent in Mancini's squad could mean he will have to wait for his chance in the team.
"It's a once in a lifetime opportunity for me," Rodwell told reporters. "I believe in my ability and that whatever squad I join, I can add to it.
"I'm looking forward to working with all my new team-mates, particularly Yaya Toure, who's a great player.
"I look up to him and he's a great role model."
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Rodwell was an unused substitute in England's 2-1 friendly win over Italy on Wednesday, and is fully aware that he could spend lengthy spells on the bench at the Etihad Stadium before establishing himself as a regular.
"It might take some time but that's what I’m there for," Rodwell added. "I know I'll have to be patient but I'm young and have time on my side.
"That's the great thing for me. I'll learn a lot and hopefully improve my game as well.
"They won the league last year and will want to improve on that by winning the Champions League. It's so exciting to be part of that."