I think he wil stay in Atletico-Mg, he wants to stay, as in atletico is the only place he has played good football in his life.
He belongs to Vasco who might bring him back, I don't know....but an Attack with Guilherme and Romario would not be good as both are prolific goalscorers that need service and don't create nothing to no one!
NOw for the national team , it is the first time he has been called up, and it is not an experiment because it is a WC qualifiying game, and their is no time for experiments!
He was choosen BEFORE the overated Amoroso, and jardel!
And in my opinion Luxemburgo did do the right thing to call Guilherme instead of those 2!
