Del Piero has spent the last two seasons at the A-League outfit, but their latest campaign came to an end on Friday with a 2-1 defeat at the hands of Melbourne Victory in the first elimination final.
The 39-year-old is out of contract, and Farina is unsure whether he will be back at the club next season.
"Well that we don't know yet," he said. "That's something (we'll wait on) out of respect for what Alessandro wants to do.
"Discussions have to be had. I think it'll be relatively quick now in terms of discussions and a decision.
"That's up to Alessandro. He'll most probably need a bit of time after this game to settle his head.
"I haven't personally spoken to Alessandro about anything. That's something that will take place and will be made public after all decisions are made.
"He's been fantastic for Australian football both on the field and off the field. And for Sydney as a city and as a club.
"He's been wonderful, but we've got to respect and see what he wants to do.
"The football club will always move forward, irrespective of whether one player stays or goes. Nothing's built around one individual."
