Fans of the Seattle Sounders could be forgiven for feeling a bit superstitious on Sunday when Nelson Valdez was scratched from the starting 11. The 2015 squad has endured international call-ups, self-inflicted absences (Clint Dempsey, Marco Pappa), in-game injuries (Román Torres), training injuries (Chad Marshall), warmup injuries (Valdez), sleeping injuries (Erik Friberg) and injuries they can't be bothered to mention (Zach Scott). But is the team truly more snakebit than its peers?
The plot above seeks to place the Sounders' roster usage - as far as can be measured by share of minutes played - in league context of the past 3 seasons. Seattle has used its top 8 players, by playing time, substantially less than it did last season (~7% fewer minutes) and significantly less than the league average (note the 1 standard deviation error bars on the blue line of the top graph). We've taken a look at lineup usage through the distribution of minutes played on a couple of occasions, for different reasons: here, as now, as a proxy for injury; here, as a proxy for managerial selection. Blaming any single factor is difficult without knowing the coach's mind... and of course the truth is probably a combination of player unavailability, player fitness, and player ineffectiveness. No matter the ambiguity of the cause, we know that lineup use reflects performance:
Whether you choose the top 4,6,8,10, 12,16 players on a roster, sorted by field time, their share of minutes is positively correlated with team success. This may possibly indicate a bit more influence managerial discretion in the data than player unavailability - injuries strike all teams and not always in the most key positions, but a struggling team often has little choice but to mix up the playing ingredients.
Seattle has been forced into a fairly skewed utilization of its roster in 2015 - its minutes share to the top 8 players is the ninth lowest of the past 3 years - but many teams have had similar struggles (and some would also cite injury as the primary culprit). The Sounders have also perhaps performed better than would be expected under the circumstances, when compared to the MLS norm. If one used the linear regression line above as a crude means of projecting points per game, Seattle would be overperforming its lineup restrictions by ~0.288, the 4th highest mark of the past three years (behind SKC and RSL in 2013...and the 2014 Sounders). Still, this is a 3-year dataset. Neither the severity of the lineup changes nor Seattle's strength under duress are truly out of keeping with league context.
It's best not to over-dramatize either element of the season. Seattle has been a bit unlucky and respectfully good at soccer. If the team plays out the season as it is capable of doing, the only fitness it will need to consider is the team ready for the MLS Cup playoffs.