This chart from yesterday by High Heat Stats MLB shows decisions are being earned by relievers in these playoffs at the highest rate since 1964. Since the playoff sample pool has grown over time (championship series started in 1969, division series started in 1995, and wild card started in 2012), this sort of outlier is even more impressive, especially since it's owed mostly to a single bullpen.
The number has dipped some after last night's game—to 58.3 percent—but it's still way out in front of the past several decades. Starting pitchers continue to throw fewer innings per start and complete fewer games, but relievers accounting for nearly 60 percent of decisions this postseason is about two times greater than this year's regular-season average of 29.5 percent. The aberration mostly stems from Kansas City relievers accounting for six of their team's eight decisions.