The Mariners entered this season with the longest active playoff drought in the four major North American professional sports leagues, attempting to make their first postseason since 2001.
On March 12, 2020, MLB announced that because of the ongoing COVID-19 pandemic, the start of the regular season would be delayed by at least two weeks in addition to the remainder of spring training being cancelled.
[1] Four days later, it was announced that the start of the season would be pushed back indefinitely due to the recommendation made by the CDC to restrict events of more than 50 people for eight weeks.
[3] The 2020 Major League Baseball season saw the adoption of many temporary rules, including universal DH, 7-inning scheduled doubleheaders, and extra innings starting with a runner on second.
All affiliated minor league seasons were canceled, leaving top prospects and depth players at the team's alternate training site in Tacoma on an expanded roster.