MLS teams’ ages, plotted against ages weighted by minutes played (season goal differentials correspond to font size). Teams above the regression line played their older players more; those below the line played their younger players more. NY is an outlier; very old by either measure. Portland, on the other hand, is very young.
Note clump of high-quality (Western conference) teams in the middle; rosters built and playing players in the prime of their career. Note also the clump of Eastern conference teams with younger rosters.
The Union are surprisingly above the curve here, despite seeming to play a lot of young players; this is because of Mondragon, Califf and Le Toux.