Brett Favre: I Know I Can Play At NFL Level But I Don't Wanna Get Hit Anymore!

47-year-old Brett Favre says he KNOWS he still has the arm to compete in the NFL ... but he just doesn't wanna get hit anymore.

The ex-NFL star says he's flattered by ATL Falcons CB Robert Alford -- who strongly feels Favre could make a comeback after their workout in Louisiana this week ... but it ain't happening.

"I could still make the throws," Favre tells TMZ Sports ... "If they promise they won't hit me, I'll play."

There's more ... Favre says he's far more concerned about the longterm effects of concussions and is invested in multiple companies -- including Prevacus and Brock USA -- in the hopes of preventing and treating brain injuries.

Favre says he feels it's his "duty" to try and make the game better and safer for future NFL players and he's touring around with Sqor Sports in hopes of doing just that.

But, when it comes to his own family members playing the game he loves, Brett says he would "strongly discourage" his grandsons from playing football based on the medical information he has today.

"Yeah, you may make a good salary ... but what happens in the end if you have enough concussions? It may be a tragic end."