6:40 AM PT -- 5/23 -- Awful news for Stefan Wilson ... the driver's team revealed he suffered a fracture of the 12th thoracic vertebrae in the crash and will now be forced to miss this weekend's big race.
The team added that Wilson stayed overnight at the hospital "for further tests and observation."
Scary moment at Indianapolis 500 practice on Monday ... Stefan Wilson was taken off the track on a stretcher after his car violently collided with a wall during a wild wreck.