If we lump together all players (both pitchers and position players) twenty-five and younger and thirty-five and older, we find that the “old” group accounted for the lowest percentage of league-wide WAR since the nineteenth century in 2017 and barely rebounded in 2018. The “young” group’s share, meanwhile, was close to a thirty-five-year high. The difference between the two proportions was at its widest since 1974.
