The Mariners could theoretically salvage the month of May from being a total installment of Disasterpiece Theatre, and are off to a good start following last night’s narrow win over the Athletics, but let’s be honest: the team has been playing well below expectations over this month. Doing some good ol-fashioned WPA (Win Probability Added) back-of-napkin math, I looked at the last 19 losses incurred by the Mariners—dating from the end of that heady home series and sweep of the Royals—to try to get at a broad sense of where, exactly, the team is underperforming, and what has been done about it and is yet to be done about it.