Has the Evolution of Bullpens Made Grinding Out At-Bats Less Effective?

Some of the best offensive teams this century have been good at grinding out at-bats to raise pitch counts. The goal was to get to the less effective middle relievers to score more runs. Ian York takes a look to see if the evolution of bullpens has made grinding out at-bats a less effective strategy than it once was.

Throughout most of the 2000s, the Red Sox were a very successful team. One of their signature offensive philosophies has been to grind out at-bats: combining patience with plate discipline to cause opposing pitchers to throw extra pitches forcing the starting pitcher out early and allowing the team to feast on the soft underbelly of their opponent’s middle relief.

In recent years, the 2013 World Series win notwithstanding, the Sox have been much less successful. Baseball is a constantly-changing game; is it possible that their 2000-era offensive approach is outdated?

The present age is one in which pitching dominates. Not only has the strike zone expanded significantly, making it easier for pitchers to throw strikes, there now seems to be much stronger middle relief pitching. Where middle relievers were once an afterthought, usually mediocre failed starters who couldn’t compete as closers, now most teams seem to have a stable of power arms who can come out in the 6th and 7th innings throwing in the mid- to upper-90s.

Has baseball made the grind-it-out at-bat a relic of history? Is it counterproductive to try to get to an opponent’s middle relief today?

By looking at the history of runs scored per inning, it can be determined if there are any trends indicating that middle relief may be entering a new period of strength. We used the wonderful Retrosheet game log database to find the average number of runs per inning, as a percentage of the team’s total runs, from 1950 through 2014. It looks like this as an animation (showing innings 1 through 10):

Some points are easy to see in this. Scoring is highest in the first inning; that is the only inning when the top of the lineup (where one hopes the best batters are) are guaranteed to bat. There is a second, smaller peak in scoring in the 4th through 6th innings as the starting pitcher starts to tire, and as the batters see the pitcher for the second and third time in the game. The home team has the lowest percentage in the 9th inning, because in about half the games the home team doesn’t bat in the 9th. Even for the visiting team, there is a detectable reduction in scoring in the 8th and 9th innings. This is more easily seen in scatter charts with 5-year-average lines to smooth the data. Here red is the home team, blue the visitors:

Here it is easy to see that the reduced scoring in the 8th and especially in the 9th is largely a product of the relief pitcher. With the advent of the closer in the 1970s and 1980s, there is quite an abrupt drop in scoring in the 9th. Scoring in the 7th and 8th innings has also reduced, though to a lesser extent and more gradually, reflecting first the general-purpose relief pitcher and then the concept of the setup man, the second-best reliever, pitching in those innings. 

The interesting inning, for our question here, is the 6th, the classic middle-relief pitcher’s inning. Here are just the most recent 25 years:

Scoring in the 6th inning peaked in the mid-2000s and has been dropping, more or less, since then. The data are limited and noisy, but this is the effect we would expect with the increased strength of middle relief. By comparison, over the same period, scoring in the 7th through 9th inning – the domain of well-established specialists – has remained roughly constant.

This is no more than a tentative hypothesis, but it may be something to follow. The Sox have already discussed moving away from their traditional strength to take a more aggressive approach at the plate this year. It is certain that they will need to continually adjust their strategy as the rest of baseball counter-adjusts.

Ian York has written about rookie struggles, an impressive start by Eduardo Rodriguez, Mike Napoli and the effect the strike zone is having on him, and Rick Porcello’s location.

Follow Ian on Twitter @iayork.

Check out Brandon Magee’s article about the Pawtucket-Boston shuttle.