Forget the Tom Brady-playing-until-45 debate ... Melvin Gordon says there's a GRIP of NFL QBs who can play to that age -- including his teammate, Philip Rivers!!
The Chargers superstar told us it's really not that hard for dudes like Brady, Rivers, Drew Brees, Matt Ryan and Russell Wilson to play forever ... 'cause they're studs who don't ever get hit like running backs do.
"I feel like those guys ... they quit when they want to, man," Gordon told TMZ Sports.