Riddle, 23, pleaded guilty in 2006 to first-degree murder of outfielder Dernell Stenson of LaGrange, Ga., as part of a plea agreement.
Riddle, originally of Harvey, Ill., and his accomplice, David Griffith, 24, were charged with kidnapping Stenson as he left a Scottsdale nightclub on Nov. 5, 2003, and stealing his SUV. Police reports show they drove to nearby Chandler, where Stenson tried to flee the vehicle. He was shot several times, became tangled in a seatbelt and was dragged more than 1,000 feet.
Griffith was sentenced to life in prison without the possibility of parole last month after pleading guilty to murder, armed robbery and kidnapping. He had faced a death sentence.
Stenson, 25, was playing for the Scottsdale Scorpions of the Arizona Fall League. The league established the Dernell Stenson Sportsmanship Award in his honor.
Copyright 2008 The Associated Press This story was not subject to the approval of Major League Baseball or its clubs.