Ronaldo has been linked with a move to Manchester City in recent months, but Mark Hughes did not want him at the club.
Italian side Siena have offered the Brazilian striker a contract.
Ronaldo said: “I thank them but I really don’t know what the future holds for me.
“I am tired because my rehabilitation work has been hard and my legs are heavy.
“I don’t know if I will continue playing or retire. I still haven’t taken a decision.
“There is no rush. I want to complete my recuperation. I could decide tomorrow or in a month. I really don’t know.”
