BUENOS AIRES, March 21 (Reuters) - Former Uruguay captain Paolo Montero, frustrated by an injury-plagued season with Argentina's San Lorenzo, says that football is making him suffer when he should be enjoying the twilight of his career.

"I can't find the reason for so many injuries," said the 34-year-old who, during nine seasons with Juventus became known as one of Europe's most ruthless defenders.

"I've tried to give everything to San Lorenzo in the last years of my career but it isn't working out," he said in a radio interview.

"Football has become a source of suffering. That can't be right, because it's what I love doing."

Montero joined the Buenos Aires club last August but has played only 10 games and has been forced to leave the field early on three occasions.

Coincidentally, Montero's coach at San Lorenzo is another of football's hard men, former Argentina captain Oscar Ruggeri.

Montero won 61 caps for Uruguay and announced his international retirement after they lost over two legs to Australia in a playoff for a place at the 2006 World Cup.