"Biggest Loser" Competitor Upgraded to Stable Condition After Bone-Shattering Fall

"Biggest Loser" competitor Sam Poueu -- who was listed in critical condition after falling several stories from a fire escape this month -- is making some serious progress in his recovery and has been upgraded to stable, TMZ has learned.

We're told doctors are still wary because Sam's status could change at any moment -- but overall, everyone's excited by his progress.

As we previously reported, Sam was celebrating a friend's birthday when he accidentally locked himself on the roof -- and fell several stories while trying to climb down a fire escape.