While a new face often prompts an uptick in results, such has not been the case with Pioli's Milan, who have only managed one win from five games since the Italian entered the dugout.
That Milan have lost seven games already in Serie A this term, netting just 11 goals from 12 games, indicates how the problems go much deeper than the manager.
Indeed, as seen in their recent 1-0 defeat to Juventus, there remains plenty of fight in the ranks, but the lack of tangible style and collective organisation - especially in the final third - is a big concern.
While Napoli's troubles are in no way comparable to that of their Milanese rivals, there is nonetheless a level of concern at the side's inability to consistently claim results this term.
At a time when Maurizio Sarri's Juventus, normally guaranteed to win the title, are themselves stuttering in their performances, Napoli are not taking advantage.
In 12 games so far this term, Napoli have drawn four times, often in instances where they should have won, such as a stalemate with Genoa last time out during which they conceded a worrying amount of possession.
There is a feeling among the Napoli faithful that, despite Ancelotti's renowned tactical acumen, the speed of their play in the final third does not match up with what supporters at the San Paolo Stadium have come to expect.
However, they will feel that the meeting with a confidence-sapped Milan side could serve as an opportunity to take proper control of a game from the start.
Recent AC Milan form: WDLWLL
Recent Napoli form: WDDLDD
Ancelotti's only long term injury concern is Kevin Malcuit, whose knee ligament injury is expected to keep him out until April.
AC Milan possible starting lineup:
Donnarumma; Conti, Duarte, Romagnoli, Hernandez; Bennacer, Bonaventura, Rebic; Calhanoglu, Suso, Piatek
Napoli possible starting lineup:
Ospina; Di Lorenzo, Koulibaly, Maksimovic, Hysaj; Fabian, Zielinski, Insigne, Callejon; Mertens, Lozano
We say: AC Milan 1-2 Napoli
Neither team looks particularly capable of claiming a victory at this moment in time and will most likely indulge in a cagey, unattractive game, but the visitors may ultimately capitalise on Milan's lack of imagination going forward and steal a winning goal.