Ken Griffey Jr. hit his first homer on the first pitch he saw at the Kingdome -- on his dad's birthday

KEN GRIFFEY JR.'S MILESTONE HOME RUNS! (From his 1st to his 600th, check out his most memorable HRs)

Ken Griffey Jr. hit his first homer on the first pitch he saw at the Kingdome -- on his dad's birthday

Ken Griffey Sr. and Jr. become the first father-son duo to ever play together

Happy Birthday to the Kid, by Mariners PR

MLB Power Rankings: The 50 Greatest Players in Seattle Mariners History, News, Scores, Highlights, Stats, and Rumors

The best Father's Day moment for every MLB team

Home Run Derby hero Ken Griffey Jr. is still the only player to ever homer off the Camden Yards warehouse

Ken Griffey Jr. hit his first homer on the first pitch he saw at the Kingdome -- on his dad's birthday

M's Griffey calls it quits

Happy Birthday to the Kid, by Mariners PR

Ken Griffey Jr. took Carlos Gonzalez, Matt Carpenter, Nolan Arenado and Adam Jones to dinner in Costa Rica

The Home Run Derby is back in Denver, where Mariners star Ken Griffey Jr. turned boos to cheers in 1998