Porzingis was sidelined for three games late last month because of the same ailment.
Knicks coach Jeff Hornacek said there was no tear in Porzingis' Achilles and team trainers have no fear of Porzingis doing further damage to his Achilles by playing on it.
The second-year big man woke up with soreness in his Achilles on Thursday following the Knicks' loss to the Philadelphia 76ers on Wednesday.
Hornacek said the injury impacted Porzingis on Wednesday, when he scored seven points and missed five of six 3-pointers, including one that would have sealed the win for the Knicks.
There are no plans for Porzingis to undergo a second MRI at the moment. He had an MRI when the injury originally occurred which showed no tear in his Achilles.
Hornacek said the Knicks might hold Porzingis out of Saturday's practice and ask him to test the injury during shootaround Sunday before the Knicks' game in Toronto.
The decision to play will rest mostly with Porzingis.
"He's got to be honest with his assessment if he can play or not," Hornacek said. "We'll kind of work with the trainers and look at it that way and make decisions."