Tracy Morgan Crash -- Walmart Says It Will Take Full Responsibility ... If Its Driver's to Blame

Walmart is stepping up ... saying it will pay expenses for the victims in the crash that left Tracy Morgan in critical condition Saturday morning if its driver is found at fault ... this according to their CEO.

Walmart President/CEO Bill Simon says they're working with investigators to figure out what led to the crash ... adding, "this is a tragedy and we are profoundly sorry that one of our trucks was involved."

Simon says, "We can't change what happened, but we will do what's right for the family of the victim and the survivors in the days and weeks ahead."