Since the late 1980s, when Tony La Russa began pitching closers for one inning, and only with a lead, the save has become a much less interesting statistic. While limiting the closer's role, it also accelerated and enhanced specialization in middle relief, giving the bullpen defined roles for two pitchers: the closer and the setup reliever.
In the 1990s, bloated pitching staffs and the constant shuttling of players from the minors to the majors defined relievers even more. Soon, many teams had two setup pitchers, one typically reserved for eighth-inning duty and the other for the seventh. If possible, a manager preferred to have one righty and one lefty available for setup duty.