An unfortunate truth about the Seattle Mariners is that their long standing ineptitude has mostly robbed them of a true rival.
* dusts off my best third grade book report *
Webster’s Dictionary defines rival as “one of two or more striving to reach or obtain something that only one can possess”. While that is inherently true of every sporting fixture—only one team can win the game—the exclusive possession bit kind of leaves the Mariners out. A few teams are certainly capable of winning the division in any given year, but only one can ultimately possess the AL West crown.