Complex sentence: In summer 2004 he was signed by newly promoted team Fiorentina, by buying half of the registration rights from Brescia, but on January 2005, Fiorentina immediately bought all of the rights.
Split into simpler sentences: In summer 2004 he was signed by newly promoted team Fiorentina, by buying half of the registration rights from Brescia. On January 2005, Fiorentina immediately bought all of the rights.