A Seattle Mariners Nike Cooperstown Throwback White MLB Jersey hand signed by Ken Griffey Jr. The item and signature are in excellent condition. Ken is a former professional outfielder. He is a member of the Baseball Hall of Fame, 13x All-Star, AL MVP, 10x Gold Glove Award winner & 7x Silver Slugger Award winner. AUTHENTICATION: The item has been tagged with a SmarTag powered by Prova Technology, which gives you digital access to the items authentication records, including a proof picture from the signing.