Five-time NBA champion Tim Duncan, the San Antonio Spurs' 40-year-old superstar big man, says he does not know if he has played the final game of his NBA career. The future of Duncan and Argentine guard Manu Ginobili with the perennial title contenders became the key subject for the Spurs on Friday after a 113-99 playoff loss to Oklahoma City ended their season. Duncan, who has a $6.4 million player option for next season in what would be his 20th NBA campaign, pointed to the sky as he walked off the court following Thursday's loss but gave no hint of what his future might entail.
