The 33-year-old returned to Fiorentina after his loan deal with Turkish club Besiktas.
Boateng undertook the mandatory test before he could join his teammates for training.
He joined the team's first training on Sunday, August 23 as the La Viola begin preparations ahead of new campaign next season.
There have been talks the Ghanaian International wants a move out of the club after failing to impress coach Montella.
Boateng had to look elsewhere for more playing time, seeing him join Besiktas in January.
The former AC Milan star is likely to leave the Serie A before the transfer window ends.