Johnny Manziel Says The Rock Can Save the XFL, 'But I'm Retired, Dude'

Johnny Manziel LOVES the fact The Rock just bought the XFL -- but don't expect to see the QB sign a contract anytime soon. "I'm retired, dude," Manziel told TMZ Sports outside of Saddle Ranch in L.A. on Friday. Manziel's only 27 years old -- and…