On April 6, 1977 – – For the second time in nine years, a new franchise makes its major league debut in Seattle, Washington. The Seattle Mariners lose their first regular season game at the Kingdometo Frank Tanana and the Angels, 7 – 0. Joe Rudi is 3 for 4 with a homer and 4 RBIs. The loser for the M’s is Diego Segui‚ who pitched in the Seattle Pilots’ Opener in 1969‚ a 4 – 3 loss at Anaheim. Segui is the only player to appear for both the Pilots and the Mariners.

 

Source:

Baseball Reference April 6