Zion Williamson remains unsure when he will make his NBA debut as the New Orleans Pelicans forward resumed full practice on Thursday.

Williamson, the top pick in the 2019 NBA Draft, underwent knee surgery in October and is yet to play for the Pelicans.

The 19-year-old started full practice but is still uncertain about when he will be ready to feature for the team.

"I couldn't tell you," Williamson told a news conference.

"It'll probably be one of those moments where, just like when it came to my college decision, I woke up and I just know.

"I'm not trying to like just say something just to say something. That's my honest answer.

"I'll probably have to wake up one day and be like all right, Griff [David Griffin], Trajan [Langdon], coach, training staff, I'm ready, let me go."

Without Williamson, the Pelicans have struggled to an 11-23 record despite being on a four-game winning streak.

While delighted to be back in full practice, Williamson said it was tough to accept not playing.

"It's been a hard balance because I am 19, I do just want to get back out there," he said.

"But from a professional standpoint I do have to look at longevity."