Ronaldo will be sidelined at least a month after breaking his hand in a league match over the weekend.

Doctors said Monday the Brazilian forward broke two bones in his left hand after a fall 20 minutes into Corinthians' 3-0 loss to Palmeiras on Sunday. Ronaldo could miss up to eight Brazilian league matches because of the injury.

Corinthians doctor Paulo de Faria says Ronaldo will miss four to five weeks because of the injury, and further exams would determine whether surgery was needed.

"The hand is still very swollen," Faria said. "We will have to conduct more exams. The recovery time with or without surgery is the same, but the surgery may be more effective."

Ronaldo, less than five months into a successful return from the third serious knee injury of his career, had to be replaced after falling at Prudentao Stadium in Presidente Prudente. Ronaldo was trying to dribble past Palmeiras midfielder Souza when he was bumped and lost his balance. He tried to soften his fall, but ended going down awkwardly on top of his hand.

Ronaldo stood up and left the pitch on his own, but was holding his hand in obvious pain. He later appeared near the field with his left arm supported by a brace.

Ronaldo entered Sunday's match as Corinthians' top player, having scored six goals in five matches. He was thriving in his comeback, and had already helped Corinthians win the traditional Sao Paulo state championship and the Brazilian Cup.