 Joseph Michael " Joe " Nathan ( born November 22 , 1974 ) is an American professional baseball pitcher for the Chicago Cubs of Major League Baseball ( MLB ) . Nathan started out his baseball career as a shortstop in high school and while at Stony Brook University , but converted to a pitcher after being drafted by the San Francisco Giants . He worked his way through the minor leagues , alternating between spots in the rotation and the bullpen . After a few years of splitting time between the majors and the minors , Nathan had a breakout season as a setup man for the Giants in 2003 . That offseason , Nathan was traded to the Minnesota Twins and became their closer . 
