The Seattle Mariners on Monday announced that Hall of Famer and franchise legend Ken Griffey Jr. has joined the club's ownership group. The investment makes Griffey the first former player to hold partnership interest in the Mariners. The size of Griffey's stake in the team was not disclosed. 

Griffey, now 51, has served as a special consultant to the team since 2011. 

"On behalf of all of the partners, I want to welcome Ken," Mariners chairman and managing partner John Stanton said Monday. "Ken has been an icon of our franchise, on and off the field, for over three decades and we are thrilled that he is joining us as a partner. His knowledge of the game, love of the Mariner fans, his experiences as a player, his passion for community service and his desire to help grow our sport will be a welcome, and invaluable, additional voice."

Griffey, who was elected into the Hall of Fame on the first ballot in 2016, spent 13 of his 22 big-league seasons with Seattle. Of his 630 career home runs, 417 came with the Mariners. As well, 10 of his 13 All-Star appearances came in a Mariners uniform. He was originally drafted by the Mariners with the first overall pick in 1987. The relationship lasted until his was traded to the Reds in February of 2000. In 2016, Griffey's No. 24 became the first number retired by the Mariners. 

"As I said in my Hall of Fame speech, I'm very proud to be a Seattle Mariner," Griffey said on Monday. "I'm excited for this incredible opportunity to join John and the rest of the Mariners partnership group. This is a dream come true because of the relationship I've always had with the team, its fans, and the city of Seattle. I view this as another way to continue to give back to an organization and community that has always supported me, and my family. I'm looking forward to continuing to contribute to this organization's success in any way possible."

Earlier this year, Griffey was named as a senior advisor to MLB commissioner Rob Manfred. 

The Mariners are coming off their first 90-win campaign since 2003, but they haven't made the postseason since 2001, which is the longest playoff drought in major men's North American professional sports.