Wesley Matthews and DeAndre Jordan, who both have expiring contracts and could be buyout candidates, will also go to the Knicks. Trey Burke, who is averaging 11.8 points this season, is headed to the Mavericks along with Porzingis, Courtney Lee and Tim Hardaway Jr.
The deal came together after Porziņģis met with Knicks management Thursday for less than five minutes and left franchise officials with the impression that he wanted to be traded, undisclosed sources told ESPN.
The Knicks will get the Mavericks' unprotected first-round pick two years after they send one to Atlanta to complete their draft-day deal for Luka Doncic, and another first-round pick that is protected two years after that, sources told ESPN's Ian Begley and Adrian Wojnarowski. Those picks could come as soon as 2021 and 2023 if Dallas does not move into the top five this year.
The Mavericks are hoping to re-sign the 7-foot-3 Porziņģis, who will be a restricted free agent, to a long-term deal this summer, and they are confident that Doncic and veteran Dirk Nowitzki can play significant roles in making that happen, a source told ESPN.
"He loves Luka and Dirk," an unnamed source told ESPN about Porziņģis, whose other option would be to sacrifice millions by playing on a one-year qualifying offer.
Porziņģis spent time with Doncic in Madrid last summer while he recovered from injury at the Real Madrid facility, more unnamed sources said.
"We obviously think Porzingis is a great young talent, similar in many ways to Dirk," coach Rick Carlisle said on radio station 103.3 FM ESPN. "This is kind of a Dirk-and-Nash type of situation, only these guys are taller."
Porziņģis tweeted to say: "New York will always have a special place in my heart. Grateful for everybody who made this journey so special for my family and I."
New York will always have a special place in my heart.— Kristaps Porzingis (@kporzee) February 1, 2019
Grateful for everybody who made this journey so special for my family and I. pic.twitter.com/q923ul3Wk4
There has been a strong disconnect between Porzingis and Knicks management in recent years, and it culminated in Thursday's meeting. He expressed concerns on the state of the franchise and his future with the organization, unnamed sources apparently said.
Porziņģis, the No. 4 overall pick in the 2015 NBA draft, was averaging a career-best 22.7 points before he was lost because of a left knee injury during a breakout All-Star season in 2017-18. He also was averaging 6.6 rebounds and 2.4 blocks.
The Knicks (10-40) have struggled without the 23-year-old Porziņģis, who has been sidelined for nearly a year because of an injury. He was evaluated in January by the team's medical staff, which confirmed his knee is healing well.
He recently worked out with a coach on the court for roughly 45 minutes.