Leveraging bullpen depth effectively has become a hybrid of science and art, with the bias now heavily toward science. Teams with multiple, high-leverage relievers have a distinct match-up advantage as the innings provided by starting pitchers have decreased through the years.
Furthermore, one-batter specialists - whose usage had increased through the decades - have seen their role almost eliminated due to the three-batter rule. However, the use of multi-inning relievers has regained popularity, especially as teams leverage “openers” on a more regular basis in both the regular and postseason.
For the Braves, proof of the impact of an effective, deep bullpen can be seen in the results of the 2021.