Webber also broke shoulder in bike crash
The Australian driver's recovery to fitness from a badly broken right leg has been well documented ahead of the 2009 season.
But, as he arrives in his native country ahead of next week's Melbourne season opener, Webber – who is still limping – told local newspaper The Age the full extent to his injuries was not previously disclosed.
He revealed that, before returning to Europe in the wake of the crash, he discovered some more bad news upon being visited by a physiotherapist.
"We discovered that I actually had a fracture in my left shoulder," the 32-year-old, who drives for Red Bull, said.
"It's just how I landed — with a backpack on and the weight in that, I crushed part of the bone. Frankly, with how bad the leg was, it was a real kick in the nuts.
"Luckily it didn't need surgery, but it made it harder getting around on crutches and trying to sleep," Webber added.
He also revealed that he sometimes questioned his own confidence that he would be back in action when the 2009 car was rolled out at a Spanish test circuit in February.
Webber, who did manage the deadline, said "a lot of people" told him "that first test wasn't possible".
"I basically guaranteed (team owner) Dietrich (Mateschitz) that I'd be at the first test on the 11th of February, and there were times I thought that was probably a little naive of me to say that."