Yes it's a brazilian slang and it basically means to fight for the grasp of sth/sb.
Take a look to that picture :
http://www.planetadofutebol.com/phot..._6834_1698.jpg
they are fighting for the grasp of the football.In relation to the song the brunette is the ball and the footballers are the friends. There are allways risks when you fight for sth/sb, you can be either the winner or the looser. And when he says "só que eu não vou em bola dividida" it means that he doesn't like to take risks.