The star rookie left Rogers Arena on a stretcher and was taken to a hospital after a collision in the Canucks' 4-3 overtime win over the New York Islanders on Monday.
Boeser fell into an open gate at the players' bench after trying to make a hit on Islanders forward Cal Clutterbuck.
The Canucks said Tuesday that he was diagnosed with a soft-tissue injury and a nonstructural, non-displaced fracture of a transverse process in his lower back.
The transverse process is a bony projection off the side of a vertebra that serves as a point for ligament attachment. Each vertebrae has a transverse process on each side.
The 21-year-old Boeser leads all NHL rookies with 29 goals and is second among rookies with 55 points in 62 games.