The Seattle Mariners are a Major League Baseball team based in Seattle , Washington . They are in the West Division of the American League. The team came into existence in 1977 as an American League (AL) expansion team. From 1977 to 1988 Seattle went through seven managers and dozens of starting lineups, finishing no better than fourth place in the West Division. The club's history up until the 1990s was quite poor, without a winning season until 1991. The early history of the team during the 1970s and 80s is characterized by perennial non-achievement. Major league baseball returned to Seattle in 1977 when the Mariners joined the AL along with the Toronto Blue Jays. Seattle 's early teams featured outfielders Ruppert Jones , Leon Roberts, and Lee Stanton and infielders Bruce Bochte and Dan Meyer. Mike Parrott and Enrique Romo led the pitching staff. In 1980 the Mariners lost 103 games and finished the season in the last place. The team faced declining phase as they could not achieve laurels in these seasons.Seattle Mariners Jerseys