Coach Rick Carlisle said Porzingis' status could be a game-time decision.
"Look, a lot of this is going to be hour-to-hour, minute-to-minute type stuff, probably into the later stages of tomorrow," Carlisle said Monday. "The game is at [9 p.m. ET] tomorrow night, so it may be late in the day, late in the evening, before we know for sure.
"I will say that there's nothing on the MRI that has ruled him out a day before the game, and that's good news. I think we can take some stock in that, and we will just have to see where we are tomorrow."
Mavs star Luka Doncic was a game-time decision Sunday afternoon with a sprained left ankle and ended up delivering a historic showing, putting the exclamation point on a 43-point, 17-rebound, 13-assist performance by drilling an overtime buzzer-beater to even the series. Carlisle said Doncic's ankle is "doing well" and would hopefully benefit from an off-day.
Porzingis, who missed a season and a half after tearing the ACL in his left knee in what ended up being his final game with the New York Knicks, has dealt with right knee soreness periodically throughout this season. It caused him to miss a stretch of 10 games in the middle of the season, beginning when he was a late scratch before a New Year's Eve game in Oklahoma City.
"From what I understand, this situation is different than the one in January," Carlisle said. "That's all I can tell you. That's all I really want to get into."
Porzingis was listed as questionable before Game 2 with right knee soreness but played 36 minutes in the Mavs' win, scoring 23 points and grabbing seven rebounds. It was not listed on the official injury report before the next two games, but Carlisle said he received word about 35 minutes before Game 4 that Porzingis was experiencing knee soreness again and would need to sit out.
Porzingis, who was ejected early in the third quarter of Dallas' Game 1 loss, has averaged 23.7 points and 8.7 rebounds in the first playoff series of his career.