Presented is an extremely rare offering: The lineup card from the game on August 31, 1990, when the Seattle Mariners hosted the Kansas City Royals at the Kingdome, and Ken Griffey Sr. and Ken Griffey Jr. became the first father and son in MLB history to play in the same game. Ken Griffey Sr. batted 2nd and played left field. Ken Griffey Jr. batted third and played center field. The offered line-up card measures 5.5x7.25". The top of the lineup card reads, "1990 OFFICIAL BATTING ORDER/SEATTLE." The back of the lineup card displays the 1990 Seattle Kingdome Ground Rules. The lineup card is dated as "8/31/9" by an unknown hand. It is signed in blue marker by both, in big and bold signatures. Seattle manager Jim Lefebvre signed the lineup card at the bottom. The game was a 5-2 Seattle victory. The Griffey family wasted no time in being productive. In the bottom of the first inning, Ken Griffey Sr. and his Hall of Fame son hit back-to-back singles off Kansas City starter Storm Davis and each later scored in a three-run Seattle inning. Ken Griffey Sr. was part of the "Big Red Machine" of the Cincinnati Reds, and he batted a career .296 with 152 home runs and 200 steals. Ken Griffey Jr., mostly playing with Seattle and the Cincinnati Reds, batted a career .284, with an amazing 630 home runs. The offered signed lineup appears to be the back page, as there were likely a few carbon copies above, so the handwriting went through. The signed lineup card is in EXCELLENT condition, and it comes with a PSA LOA for the signatures.