 Nathan was promoted to the San Francisco Giants on April 20 , 1999 , taking the roster spot of superstar <unk> Barry Bonds , who went on the disabled list after left elbow surgery . He made his major league debut the next day , pitching seven shutout innings and winning his first major league decision against the Florida Marlins , 4 – 0 . He then divided the rest of the season between the AAA Fresno <unk> and the Giants , going 6 – 4 with the <unk> and 7 – 4 and 4 @.@ 18 with the Giants , earning his first career save on May 16 against the Houston <unk> . 
