Jim Brown: Sticks Up For Johnny Manziel ... 'I'm For Him'

Legendary Browns running back Jim Brown switched to defense Tuesday ... coming to the rescue of Johnny Manziel ... saying his partying ways won't keep him from being great.

Brown appeared on "The Herd" on FS1 ... and when guest host Jason Whitlock turned the topic to Johnny Football ... Jim seriously gushed about the young QB.

Manziel has yet to fully win over the Cleveland fan base ... so an endorsement from the franchise's most celebrated player is a BIG deal.