Sydney FC announced on Friday that Del Piero had "agreed to finalise details on a contract with the Sky Blues", as chief executive Tony Pignata and Australian player agent Lou Sticca flew out to Italy to secure the 37-year-old's signature.
But Del Piero's manager, his brother Stefano, believes it is premature to consider the deal as complete, despite making it clear he considers Sydney FC's offer as a "serious" one.
"Obviously things were misinterpreted," Stefano Del Piero told Italian news agency ANSA. "We still have to properly analyse the project.
"(The offer) has not left Alessandro indifferent, we're talking about a two-year deal.
"It's a serious offer but that doesn't mean everything's decided."
Swiss Super League club Sion believed they were close to luring Del Piero to play for them last week but were eventually turned down by the former Juventus forward.
Del Piero had reportedly also attracted interest from Celtic and Tottenham but Sydney FC have now seemingly moved to the front of the queue.
Pignata and Sticca had hoped to have the deal with Del Piero confirmed by Monday.
However, the player's brother has cautioned there is still some work to do before the Italian veteran commits to playing in the A-League.
"We are still seriously analysing Sydney's offer but we haven't decided anything yet," he said.
"And it's too early to say we will have decided by Monday."
Del Piero is understood to be interested in the possibility of playing his final season in the Australian summer rather than a European winter.
The forward played 705 games for Juventus in 19 seasons, scoring 289 goals.
Del Piero also earned 91 caps for Italy and scored 27 international goals.