AC Milan striker Ronaldo said today he was still to make a decision about his playing career after undergoing knee surgery.

Surgeons who operated on the 31-year-old have said he would need nine months of rehabilitation after rupturing a ligament in his left knee earlier this month.

"I haven't decided yet what I should do," the three-times World Player of the Year told a news conference before leaving the Pitie-Salpetriere hospital in Paris. "I have the will to carry on playing, this is what my heart is telling me to do. But my body is giving me signs that it is tiring and needs rest.

"I know that physically and mentally it will be very hard."

Ronaldo sustained two serious injuries to his right knee while playing for Inter Milan in 1999 and 2000 but recovered to help Brazil win the 2002 World Cup.

He went on to play for Real Madrid before joining AC Milan in January 2007.