Lopez, 27, averaged 9.6 points, 6.7 rebounds and 1.4 blocks with per game with 17 double doubles for the Portland Trail Blazers last season despite missing 23 games because of a broken wrist. Lopez can't officially sign with the Knicks until July 9.
Adrian Wojnarowski of Yahoo! Sports first reported the deal Friday.
The Knicks are still holding out hope that Jordan might choose to take a max-level contract with New York over the Clippers or Dallas Mavericks, in which case Lopez's deal would be void.
With New Orleans, Lopez developed a stronger offensive game averaging a career-high 11.3 points per game after putting up six points or less in three of his four years with Phoenix. The Trail Blazers aqcuired Lopez via trade in 2013.
The cross-country move will put the defensive-minded Lopez in close proximity to his twin brother, Brook Lopez, who has also agreed to return to the Brooklyn Nets on a three-year deal worth $60 million.
Follow Matt Wilhalme on Twitter @mattwilhalme