Juve fought off strong competition from the Gunners to sign Melo from Fiorentina for €25 million, but the defensive midfielder has failed to establish himself as a Turin favourite after a number of lacklustre performances.
After a strong start to the current campaign, his form has faded in recent weeks and has been the subject of jeers from his own supporters.
And Sacchi believes Melo’s arrival has disturbed the side and that coach Ciro Ferrara paid over the odds for the 26-year-old in order to beat Arsenal to the Samba Boy's signature.
“Melo is a great player, but he is not functional to Juve’s plans,” Sacchi told Tuttosport.
“Juventus needed a violin player, instead they chose a drummer.”
The Old Lady were recently dumped out of the Champions League at the group phase after a crushing 4-1 defeat by Bayern Munich, and reports suggest Ferrara’s position is becoming increasingly unstable.
Meanwhile, speculation continues to link trio Melo, David Trezeguet and Amauri with a transfer away from the Italian giants during the January transfer window.
“Error upon error has been committed in Turin,” Sacchi concluded.
“On Tuesday, fans were even calling for the people who took the club to Serie B.”
