Ravasi told the Italian radio station RTL 102.5 on Thursday that he believes the Pope could take such a step because of his personality.
Despite his physical ailments, he has so far refused to do so.
But, Ravasi continued: "If he found himself in a situation in which his ability to have direct contact with people was severely restricted, then I believe he could decide to resign."
Ravasi recalled that Pope Francis, according to his own statement, had already handed over a conditional letter of resignation to the Cardinal Secretary of State at the beginning of his pontificate.
Regarding the Pope's current condition, Ravasi said that according to the information provided by the Vatican, the situation is "complex but not critical".