Zion Williamson will miss six to eight weeks following surgery on a torn right lateral meniscus, the Pelicans announced Monday.

The No. 1 pick in this year’s draft was already expected to miss time stemming from issues with his knee, which had been previously described as not very serious.

Williamson had a right knee sprain during his lone season at Duke, and the 19-year-old was shut down during summer league play after playing just nine minutes due to pain in his left knee.

The injury is a blow to the rebuilt Pelicans and the NBA — New Orleans has 30 games on national TV this season, beginning with Tuesday’s season opener against the defending champion Raptors.

The Pelicans’ expected win total dropped from 38.5 to 35.5 following the news of his procedure.

“We have good depth,” coach Alvin Gentry said of Williamson’s initial injury announcement last week, ahead of a preseason tilt with the Knicks. “That’s the thing [VP] Dave Griffin has done – from the draft and trades. Just from the free-agent market. … It will be opportunity to play guys and shift guys around and play them in different positions.’’