The 36-year-old former New Zealand international was out of contract at the end of last season but decided to play on after completing a full recovery from a hamstring injury that forced him to sit out the last two months of the campaign.
Peet has replaced Jackson Hastings with new signing Cade Cust, who will provide competition for the half-back spots with Harry Smith, an ever-present in 2021, and says 18-year-old Logan Astley could also get game time this year.
As captain, Leuluai is sure to play a pivotal role but Peet is keen not to overload him.
"That's the plan, in training as well as in games," he said. "I am hoping we can stay healthy so we can rotate our senior players.
"Rotation is part of my philosophy, sometimes to freshen up the team to take a different approach some weeks.
"You've got to look where he's at in his career and also Harry and Cade where they're at, even Logan, so giving Tommy a rest some weeks I think will be smart business."
Peet will also have Australian utility back Jai Field at his disposal after being restricted by injury to just four appearances in his first season in England.
"I want as many selection headaches as I can, that's when I'll start to earn my money," Peet added.
"The more selection headaches I can have this year, the better it will be for Wigan."
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