The Portugal superstar joined Juve from Real Madrid in the summer of 2018.
In his first two seasons with the Bianconeri, the 35-year-old has netted an impressive 60 goals in 89 appearances across all competitions.
PSG has been touted as a possible destination, as has a return to Spain with Real.
Ronaldo has enjoyed a fine start to the current season, scoring eight goals from six appearances.
But Di Marzio admits the financial impact of the coronavirus could potentially force Juve's hand.
Asked if he believes Ronaldo will stay in Turin, Di Marzio told Tribalfootball.com: "I don't know if he will stay.
"This summer I had some doubts, even if I never talked about it.
"After being eliminated from the Champions League like that, after winning two league titles, I thought he might want to leave to go and win elsewhere, also because Juventus are experiencing economic difficulties, they have budget losses.
"I thought he could go away, then they thought together that the journey was not over. These are characters who decide their time to leave, as he did at Real Madrid. For the future it will depend on how the season goes.
"That said, it brings with it such a high salary that in a football in crisis with Covid (little merchandising, no fans at the stadium ...) it is a very onerous operation, it is only for those who have a lot of money and don't worry about it."