Devastating news for the OKC Thunder ... Chet Holmgren, the No. 2 overall pick in the 2022 NBA draft, is expected to miss his entire rookie season due to a foot injury.

Shams Charania of The Athletic reported on Wednesday that the Thunder fear Holmgren -- who stands 7'0" tall and weighs 190 lbs -- suffered ligament damage in his foot.

The worst possible scenario was confirmed just minutes ago -- he suffered a Lisfranc injury to his right foot, according to ESPN's Adrian Wojnarowski.

Lisfranc injuries vary widely in seriousness ... but often require surgery to the midfoot, where bones are broken and/or ligaments torn. The injury isn't particularly common, but has occurred to NBA players in the past.

Oklahoma City selected Holmgren behind Duke star Paolo Banchero, who went to the Orlando Magic, hoping Chet could be the cornerstone of their franchise moving forward.

Holmgren sustained the foot injury in Jamal Crawford's Pro-Am game in Seattle ... where he was shown limping awkwardly after guarding LeBron James.

In the clip, you see LBJ one-on-one with Chet, who was in retreat mode, and after the 7-footer contested James' bucket, he appears to favor his right foot.

Thunder GM Sam Presti released a statement on Holmgren's injury ... saying, "Certainly, we are disappointed for Chet, especially given the excitement he had about getting on the floor with his teammates this season.

"We know Chet has a long career ahead of him within our organization and the Oklahoma City community. One of the things that most impressed us during the process of selecting Chet was his determination and focus."

"We expect that same tenacity will carry him through this period of time as we work together and support him during his rehabilitation."