The experienced Kiwi will rejoin the club with whom he made his first-grade debut in 2003.
He spent two seasons at the Warriors before he went to England and he has been with Wigan since 2007.
“I also had a real desire to go back to where it all started,” he said.
Leuluai, whose Kiwis debut also came in 2003, has played 30 Tests, one more than his father, James, who represented New Zealand from 1979 to 1986.
While the Warriors have negotiated a three-year deal with Leuluai, the Auckland-based club say they also want to retain five-eighth James Maloney, who is off contract at the end of next season and being chased by up to eight clubs.
New coach Brian McClennan said the Warriors knew Maloney was talking to other clubs, which was his right, “but he also knows we want him at Mt Smart Stadium”.