The departure of Scudetto-winning manager Luciano Spalletti has clearly had a negative effect, and the man chosen as his replacement, Rudi Garcia, was dismissed in November. Now, his successor Walter Mazzarri could face the same fate.
Garcia's three defeats in 12 league games brought an early end to his time at Napoli, but things have gone from bad to worse since Mazzarri took over, with his side suffering four league defeats in just seven games.
A 4-0 loss at home to Frosinone in December also saw them exit the Coppa Italia at the first hurdle, and they are now without leading scorer Victor Osimhen, with the Nigerian participating in the African Cup of Nations.
At the halfway point last season, Napoli had lost just once, and were well on their way to the title with 50 points in the bag and a 12-point advantage over AC Milan.
This season, at the same stage, they find themselves in ninth place, having collected just 28 points, and are 20 points adrift of leaders Inter Milan. They now face a battle to even achieve a top-four finish.
The gap to fourth-placed Fiorentina is far from insurmountable, with Napoli just five points behind, but they also have the likes of Bologna, Lazio, Atalanta and AS Roma ahead of them.
A home game against the bottom-of-the-table side may seem like the perfect chance to kickstart their season, but Salernitana's recent form make them an opponent not to be taken lightly.
While Napoli slumped to a 3-0 defeat by Torino last weekend, Salernitana will make the short trip from Salerno to Naples for the "Derby della Campania" having almost held Juventus to a draw in their last game.
After taking a first-half lead, Salernitana then went down to 10 men early in the second half, and were holding on for a point until Juve found a winner in stoppage time.
Napoli have taken just one point from their last three games whereas Salernitana have earned themselves four, giving them a fighting chance of escaping the relegation zone, with just three points separating them from Cagliari in 17th.
Before their loss to Juventus, they earned just their second win of the season away to fellow strugglers Hellas Verona, and before that, Salernitana held Milan to a 2-2 draw.
Garcia's last win in charge at Napoli was a 2-0 victory away to Salernitana in November, now Mazzarri is in desperate need to beat the same opposition to avoid seeing his second spell as manager at the club end in disaster.
Inter can stretch their lead at the top to five points when they travel to face Monza on Saturday, with Juventus not in action until Tuesday when they host Sassuolo, the only side to beat them this season.
Milan are on a four-game unbeaten run, but their resurgence faces a stern test when they host Roma on Sunday, while Fiorentina look to bounce back from their defeat by Sassuolo when they welcome Udinese on Sunday.
