Top 5 reasons Johnny Manziel should not be the Cleveland Browns starter

1. Immaturity – The NFL has had its share of QBs who lack maturity coming into the league and starting right away. And more often than not the results are not impressive: JaMarcus Russell, Matt Leinart and Vince Young all came in strong but their attitudes and inability to learn from mistakes or stop making bad personal decisions ultimately led to all of them going from Top 10 picks to massive busts. Manziel simply does not have the mental makeup to be a starting NFL QB right now. And his middle-finger move on a nationally televised Monday Night Football game did very little to assuage those beliefs.