The 37-year-old Juventus captain is a hero in Turin, having scored 290 goals in 704 games, but the board has not renewed his contract and is likely to head to the United States next term.
Over 19 years, Del Piero has won six Serie A titles, one Coppa Italia, one Champions League and an Intercontinental Cup, as well as the 2006 World Cup with Italy.
That same year as the Azzurri's triumph in Berlin, he took a step down to Serie B - Italian football's second tier - after Juve were relegated following a match-fixing scandal.
However, he helped them return straight back to the top flight as champions.
Last week he bid an emotional farewell to Serie A, typically scoring as Juventus beat Atalanta 3-1 to become only the third side to go an entire campaign unbeaten having won their first official title since 2003 the week before.
After being substituted in the second half, he accepted the invitation to stand in front of the Juventus Stadium's Curva Sud and the applause of teary-eyed ultra supporters, before heading over to the other side of the ground and receiving a similar ovation.
"I've never seen such a thing before. Let's say that the fans won us another title," said the number 10 after his tribute.
"What happened today is something incredibly beautiful, the bond with these people goes beyond anything else."
Should Juventus win on Sunday it will be their 10th Coppa Italia and with it their third domestic double.
THRILLING BRAND
For opponents Napoli it would be their fourth cup triumph, the first since 1987 and first silverware since their 1990 Serie A title and Italian Supercoppa win, back in Diego Maradona's heyday.
It has been a up-and-down season for Napoli, who missed out on Champions League football to Udinese at the weekend, while their thrilling brand of counter-attacking football in European competition captivated fans at home and abroad.
However, many felt that they had the chance to challenge for the Italian title and missing out on the Champions League has meant that some of their key players, including playmaker Ezequiel Lavezzi, have been the subject of transfer speculation.
Maradona himself urged Napoli to cash-in on Lavezzi, saying that, if he were club president Aurelio De Laurentiis, he would sell to Inter Milan, who are favourites to sign the 27-year-old Argentine.
"If I were De Laurentiis I would make a good transfer, if Inter Milan offer lots of money," said Maradona.
"This is the right moment to sell him, but Inter have to pay like they did for Ronaldo."
Both teams will be backed by thousands of passionate fans, with the Stadio Olimpico expected to be a sell-out. Reports have claimed that many supporters will travel to the Italian capital without tickets.
Juventus and Napoli fans have never particularly got on and tensions between both sets of fans and Roma supporters has prompted concerns about possible safety problems in
