Tracy Morgan Accident -- Walmart Blames Him for Not Wearing Seat Belt

Tracy Morgan has only himself to blame for the horrific injuries he suffered in the accident with a Walmart truck ... because he wasn't wearing a seatbelt ... Walmart is now claiming.

According to new legal docs ... Walmart is laying blame on Tracy for NOT strapping in while riding home in a limo van in NJ back in June. The company says that's what caused most, if not all, of Tracy's injuries.

As for any responsibility falling on the driver of the Walmart tractor trailer -- the company says it can't comment because of the "ongoing investigation." Walmart won't even confirm the driver, Kevin Roper, was an employee.

Tracy sued Walmart for that accident that left him seriously injured, and killed his friend Jimmy Mack.