Sylvester Stallone Warns Other Actors Not to Do Own Stunts After Surgeries

Sylvester Stallone says he doesn't advise actors to do their own stunts in the movie biz ... and 7 surgeries oughta serve as a warning -- you listening, Tom Cruise???

The legendary action star made the revelation in an upcoming episode of his Paramount reality show, "The Family Stallone," where he said he'd undergone more than half a dozen back surgeries to deal with an injury he suffered on the set of "The Expendables" back in 2010.

Basically, "Stone Cold" Steve Austin -- who's also in the movie -- was body-slamming Sly on set ... and the dude was actually absorbing the blows, going take after take after take.

He says, "I did stupid stuff. I was directing 'Expendables' and like an idiot I’m doing take ten, take whatever, and I remember one slam and I could actually feel one bang. Steve knew. I never recovered from Expendables 1. After that film, it was never physically the same."

Sly adds .. "I’ve warned people -- don’t do your own stunts."

SS fractured his neck and needed a metal plate inserted to stabilize things -- and as he jokingly notes ... his next role might be Quasimodo in a 'Hunchback' flick.

While he might be discussing it in jest on his show -- the injuries/surgeries are quite serious ... apparently, Sylvester's doctors have told him he might need artificial discs popped into his lower spine down the line, and his wife Jennifer Flavin says on the show it's tough on the family.