Central Coast have received a much-needed boost to their A-League off-season with veteran striker Matt Simon signing on for the 2021-2022 season.

Simon, 35, has just completed his best season for years, scoring 10 goals and providing three assists to help the Mariners finish third on the table.

"This season that we just had was very successful, and after speaking to the club and talking about going around for another year it was an easy decision in the end," he said.

Simon follows Mark Birighitti, who signed on for two more years on Wednesday, while Kye Rowles committed for two more seasons last week.

The re-signings are welcome relief for the Mariners.

Last week, coach Alen Stajcic quit just days after leading them to their first A-League finals series in seven years.

The Mariners are also set for significant on-field personnel change, with Daniel De Silva the latest confirmed departure.

Young gun Alou Kuol has already confirmed a move to German Bundesliga team VfB Stuttgart while Jack Clisby departed for Perth Glory.

De Silva, who officially announced on Thursday that he's leaving the Mariners, is expected to join Macarthur FC.

Simon has already played 14 A-League seasons - 11 for the Mariners and two for Sydney FC - and 288 games, and could reach the 300-game milestone next season.

"Matty's name is synonymous with the Mariners, and we were very keen to have him return for another season," Mariners head of football Ken Schembri said.

"He had a terrific season on the pitch this season, but he also brings so much value in the dressing room as a leader and as a mentor for the young members of our squad, and that aspect of his contribution will be so important in the Mariners continued forward progress."