The woman told the New York Police Department on Thursday about the alleged attack, according to the Post, which cited law enforcement sources. The woman reportedly told police she waited more than a year to come forward because she had discussed getting $68,000 from Porzingis to keep quiet.
Porzingis' attorney, Roland G. Riopelle, denied the allegations and said they had previously referred the case to federal authorities due to the "accuser's extortionate demands."
"We are aware of the complaint that was made against Mr. Porzingis on Friday and unequivocally deny the allegations," Riopelle said. "We made a formal referral to federal law enforcement on Dec. 20, 2018, based on the accuser's extortionate demands. We also alerted the National Basketball Association months ago, and they are aware of the ongoing investigation of the accuser by federal law enforcement. We cannot comment further on an ongoing federal investigation. Please refer any questions to the Federal Bureau of Investigation or the National Basketball Association."
Porzingis was playing for the New York Knicks and had suffered a torn ACL just hours before the alleged attack, which the woman told police happened Feb. 7, 2018, at the Sky building in New York, where Porzingis lived.
The woman, who reportedly lived in the same building, said she had accepted an invitation to Porzingis' apartment before the alleged attack.
Asked if the Knicks were made aware of the incident, a team spokesperson said, "This is Kristaps' personal matter and not related to the Knicks."
An NBA spokesman said the league is aware of the situation.
National Basketball Players Association executive director Michele Roberts said in a statement that the union has "been aware of these allegations for some time, have evaluated the accuser's claims and, based on what is presently before us, stand with Kristaps."
Porzingis was traded to the Mavericks earlier this year, but he has yet to play for them, as he still is recovering from his injury.
The Knicks informed Dallas of the pending Porzingis rape allegations on a Jan. 31 trade call with NBA headquarters that finalized the blockbuster deal, league sources told ESPN's Adrian Wojnarowski.
Mavericks owner Mark Cuban, in an email to the Post, said the team is aware of the accusation, but "we have been instructed by federal authorities not to comment."
Cuban declined further comment when contacted by ESPN.
An NYPD spokesperson would not confirm the Post report, issuing this statement: "The NYPD takes sexual assault and all rape cases extremely seriously, and urges anyone who has been a victim to file a report so we can perform a comprehensive investigation, and offer support and services to survivors."
Mavericks coach Rick Carlisle said Sunday that Porzingis is not currently with the team, as it was pre-planned for him to stay back in Dallas and work out as the Mavericks traveled to face Oklahoma City. Carlisle said this situation won't affect Porzingis' availability for practice, but if he wanted to take time away from the team, the Mavericks would be open to that.
"If he wanted to take some personal time away from being on the bench or whatever, we would certainly grant him that, but that would be his call. That would be his call," Carlisle said.
ESPN's Ian Begley, Tim MacMahon and Royce Young contributed to this report.