On Aug. 31, 1990, Ken Griffey Jr. and Sr. became the first father-son teammates in MLB history

Ken Griffey, Jr., Biography, Statistics, & Facts

Out of Right Field: To Ken Griffey Jr., Father's Day always meant more

Griffey Jr.'s father recalls son's love of game, celebrates his election to Hall of Fame, New Today

Ken Griffey Sr. and Jr. become first father/son combo to appear in the same lineup

Indianapolis Indians - We celebrate #BlackHistoryMonth today by recognizing Ken Griffey, our 1973 Team MVP and the American Association Rookie of the Year who led that year's squad with a .327 average

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

WATCH: Father & son Griffey hit back-to-back HRs

How Ken Griffey Jr.'s mad dash home in 1995 saved baseball in Seattle -- and ignited a Yankees dynasty - ESPN

What father and sons have been in professional sports at the same time? - Quora

Ken Griffey Sr. and Jr. become first father/son combo to appear in the same lineup

The Legend of Ken Griffey Jr.: Ranking Top Plays, Moments That Defined 'The Kid', News, Scores, Highlights, Stats, and Rumors

Griffey Jr. hits 500th home run on Father's Day