Boateng was replaced with Dusan Vlahovic at half time during the Viola 1-0 win against SPAL on Sunday.
Performance of the former Barcelona attacker did not meet the expectation of legendary goalkeeper Gialli.
"I did not think I could play as a starter. He does not press, does not leave anyone and does not steal the ball, " Gialli lamented over the Ghana international.
"I understand that his past and his prestige is important, but it is not that of years ago. He has obvious difficulties and his physical condition is unpresentable.”
He has scored one goal in 15 matches for Fiorentina this season.