According to Shams Charania of The Athletic and Stadium, Pelle is signing a multiyear deal with the team.
The Knicks needed to fill a hole at center after starter Mitchell Robinson had surgery to repair a fractured metatarsal in his right foot at the end of March. Pelle, 28, has appeared in three games for the Knicks this season, averaging 5.3 minutes per outing.
"He's been putting in a lot of extra work," Knicks coach Tom Thibodeau told reporters on April 14. "He's still finding his way, learning the system. But his length, shot blocking, the rim protection, is huge for us."
Pelle appeared in 24 games for the Philadelphia 76ers last season, averaging 2.4 points and 3.0 rebounds in 9.7 minutes per contest.
The Knicks won their eighth consecutive game on Wednesday, a 137-127 overtime win against the Atlanta Hawks. Pelle logged nine minutes in the outing with two points and a rebound for the fourth-place Knicks.