Juventus have been docked 10 points following a new investigation into the club’s past transfer dealings.
Juve were initially handed a 15-point penalty in January but Italy’s highest sporting court overturned that decision in April and ordered the case to be re-examined.
The new ruling was announced on Monday, before the team’s game away to Empoli.
The penalty drops Juve to seventh place in Serie A, outside the European qualification spots.
Napoli have already secured the Serie A title and, before Monday’s ruling, were 17 points ahead of second-placed Juve.
In April, Italy’s Sports Guarantee Board revoked Juve’s 15-point penalty from the Italian Football Federation (FIGC) appeals court.
It asked the appeals court to revise punishments to the club and some key figures, including former Vice-chairman Pavel Nedved.
Long bans given to former Chairman Andrea Agnelli, ex-chief executive Maurizio Arrivabene and sporting directors Federico Cherubini and Fabio Paraticihave now been upheld.
If Juve beat Empoli, they will be two points behind AC Milan, who occupy the final Champions League spot, with two games to play.
Juve are also embroiled in criminal proceedings over their accounting practices, with 12 current and former key club figures including Agnelli potentially facing trial.
According to Italian news agencies, a high court hearing on 26 October will decide whether any eventual trial will be held in Turin, where the investigation has taken place, or in either Milan or Rome.