Skateboarder Bob Burnquist left the X Games venue in Los Angeles in an ambulance on Tuesday after injuring his back during Big Air practice on the MegaRamp.

Burnquist, who has a permanent MegaRamp structure in his backyard, has won the Skateboard Big Air event three times since it was introduced at X Games and is considered to be a favorite in Thursday's elimination round and Friday's finals.

Preliminary X-ray results were negative for broken bones or spinal injuries, and Burnquist was released from California Medical Center on Tuesday night and resting in his hotel on Wednesday

The 35-year-old Brazilian skateboarder withdrew from Saturday's Skateboard park event because of his injury, but still plans to compete in Skateboard Vert on Sunday and Big Air. The Big Air prelims are on Thursday and the finals are on Friday. Burnquist has participated in X Games every year since it began in 1995, collecting a total of 20 medals along the way.

"I need a new job, can I be your co Pilot?" quipped Burnquist on Tuesday in a tweet to his friend and longtime competitor Bucky Lasek, who will compete in the Skateboard Park and Vert events but is skipping Skateboard Big Air to compete as a driver in the RallyCross event.

This year could be a record year for Skateboard Big Air regardless of whether Burnquist competes. The event now features five young athletes under age 17, including 12-year old Tom Schaar, who earned his X Games invitation in April after becoming the first skateboarder to land a 1080.

Aguinaldo Melo from ESPN Brasil contributed to this report.