Charania reported the two sides will meet when the free-agency moratorium begins Sunday.
Sports Illustrated's Chris Mannix reported it's unclear whether Porzingis would re-sign with Dallas on a long-term contract but that he "forged a strong connection with Luka Doncic in his short time in Dallas and has enjoyed his experience" with team owner Mark Cuban.
This move could be part of a big offseason for the Mavericks, whom the New York Times' Marc Stein reported have shown the most interest along with the Boston Celtics in pursuing free-agent point guard Kemba Walker.
Everyone expected the Mavericks to offer Porzingis a contract after acquiring him from the New York Knicks in January. The only source of doubt was whether Dallas would go with a full max or put together a deal that reflected his health concerns.
The 23-year-old tore his ACL in February 2018 and has yet to appear in an NBA game since.
Prior to the injury, Porzingis was averaging 22.7 points and 6.6 rebounds per game while shooting 39.5 percent from three-point range. If he can deliver that kind of production, then he'll more than validate a max contract.
But durability was already a question mark for the Latvian big man. He missed 10 games as a rookie and 16 games in his second season. Given his frame (7'3" and 240 pounds), it's fair to wonder how his body will hold up.
The Philadelphia 76ers signed Joel Embiid to a max extension that included specific injury protections for the team. Perhaps Dallas will look to get similar security from Porzingis' deal.
Charania reported in January that Porzingis planned to sign his one-year, $4.5 million qualifying offer, which would allow him to become an unrestricted free agent in 2020. That might be factoring in the Mavericks' decision since he'll have a hard time turning down $158 million.