He also knows what happens when a goalkeeper leaves his comfort zone, because he spent his playing career moving through some of Italy's most demanding environments before going on to work as a goalkeeping coach and football intermediary.
Now Guglielmo Vicario has returned to Serie A with Juventus, and Franzone's assessment of the goalkeeper takes on a new relevance.
“Vicario has performed well in every place he has been, but now at Tottenham I think he has grown a lot as a goalkeeper,” Franzone told Football Presse.
“Every match Vicario is showing his qualities and has become one of the best keepers in the Premier League. For me, he has passed also this pressure test because it's not the same to play for Empoli and to play for Tottenham in the Premier League.”
Two years on, the test has changed.
Vicario has swapped Tottenham for Juventus on a season-long loan with an option to make the move permanent, returning to Italy after making 117 appearances for Spurs and helping them win the Europa League in 2025.
His first examination came on Sunday, when Luciano Spalletti handed him the gloves for Juventus' opening Serie A fixture away to Frosinone.
Vicario kept a clean sheet as Juventus won 1-0 through Gleison Bremer's first-half header, making several important interventions before being forced off in stoppage time. Mattia Perin replaced him for the closing moments.
It was hardly a spectacular debut, but for a goalkeeper it was arguably the perfect kind of beginning: Juventus won, Vicario was beaten by nobody and the new goalkeeper left the pitch with a clean sheet.
The real challenge, of course, starts now.
Franzone's view of Vicario has always been rooted in something bigger than one player's ability. He sees him as part of a tradition that has made Italy one of football's great goalkeeping countries.
“I can say that we have always had a great school of keepers that has always produced some of the greatest keepers in the world,” Franzone said.
That school is difficult to define simply through technique. Italian goalkeepers have traditionally been expected to understand positioning, concentration, decision-making and the psychological demands of the position. Franzone's own career gave him a close-up view of that culture.
He played for Como, Salernitana, Cagliari, Reggina and Piacenza, making his Serie A debut with Cagliari in 1999. He later worked as a goalkeeping coach at Cagliari and moved into coaching and football representation after his playing career.
That perspective matters when he talks about the development of modern Italian goalkeepers. Franzone has also been willing to look beyond the names who attract the most attention.
“I like a lot two keepers that maybe aren't known as the others, like Montipò and Falcone,” he said. “I think they are very good keepers and will become even better time after time.”
For Franzone, the depth of the Italian goalkeeping pool is part of the story. Vicario is not an isolated success but one of a generation that has emerged from a country where the position remains deeply embedded in the football culture.
Yet Vicario's route has been unusual.
He had to establish himself at Empoli before making the leap to Tottenham, where the demands were entirely different. Franzone believed that move would tell us whether Vicario's talent could survive a much greater level of scrutiny.
“He was in a moment where he was at a crossroads and he needed a lot to go out and try himself and learn a new football philosophy and face a new way of football and life,” Franzone said.
“And since his return, we can see the Scuffet we saw in his beginning with his talent but also more prepared from a mental point of view.”
That assessment of goalkeepers crossing borders is particularly interesting when applied to Vicario.
At Tottenham, he was no longer simply an Italian goalkeeper who had impressed in Serie A. He was a goalkeeper being judged every weekend in the Premier League, playing for one of England's biggest clubs and dealing with a completely different level of scrutiny.
Franzone believed he had answered that question. Now Juventus presents another version of the same examination.
The pressure in Turin is different from London. At Juventus, the goalkeeper is not simply expected to make saves. He is expected to be part of a team that believes competing for trophies is normal, and every mistake is examined through that expectation.
That is why Vicario's first match at Frosinone was only the beginning. The clean sheet was useful. The saves were important. The fact Juventus left with three points mattered most.
But his real test will come with the accumulation of matches, particularly when Juventus are under pressure and the goalkeeper has to provide the difference between winning and dropping points.
Franzone has been through enough of those environments to understand that the goalkeeper's development never really stops.
His own career included promotion battles, Serie A football and difficult seasons, while his later work as a coach and intermediary has given him another view of how players develop away from the pitch.
That makes his original assessment of Vicario particularly relevant now. He did not see the move to Tottenham as merely a transfer from Italy to England.
He saw it as a test. Vicario passed it. Now, at Juventus, he has another one.
And if Franzone is right about the Italian goalkeeping school, this is not the end of Vicario's development. It could be the stage that tells us whether he can move from being an excellent goalkeeper to becoming one of the defining Italian goalkeepers of his generation.