At 2.94, 3.23, and 3.36, respectively, the St. Louis Cardinals, Pittsburgh Pirates, and Chicago Cubs recorded the top three earned run averages in baseball this season. Switching over to FIP, the Cubs led the way at 3.30, with the Pirates just behind them at 3.36 and the Cardinals in fifth at 3.48. The Pirates allowed the fewest home runs (110), the Cardinals the second fewest (123), and the Cubs the third fewest (134). The Cardinals won 100 games, the Pirates won 98, and the Cubs won 97. These numbers leave no room for ambiguity. The three top teams in the National League possessed tremendous pitching staffs in 2015. Now, how they were able to achieve this magnitude of success is where it becomes interesting and proves to be yet another example as to why baseball is so fun.
Using BrooksBaseball.net, I collected pitch usage percentages of all Cardinals, Pirates, and Cubs starters who threw at least 120 innings and all "qualified" relievers. If interested, this data can be found in this Google Sheet.
As you can see, the Cardinals are predominantly a fourseamer-first pitching staff (46.99%), while the Pirates frequently turn to the sinker (this 2014 article on the Pirates and their sinkers is must-read material) and the Cubs have a relatively even mix between the two different types of fastballs with a shift in focus toward breaking balls (slider/curve usage at 31.05%, or 55% more frequently than the Pirates and 59% more frequently than the Cardinals).
Logically, the next thing to look at is pitch location. For this exercise, I once again turned to BrooksBaseball, but this time, I looked at only starting pitchers since, in my opinion, relievers would provide cloudiness to the comparison given their situational use (i.e. lefty versus lefty, righty versus righty, etc.). "Up in the zone" means the top two rows of a BrooksBaseball zone profile (click here for a visual explanation), and similarly, "Inside to LHH" and "Inside to RHH" mean the two inner columns respective to the batter's handedness (again, another visual here).
Once again, different methods used by each team's pitchers. Pirates starters emphasize staying down in the zone and in on the hands of hitters, especially lefties. On the other hand, the Cardinals, a fourseamer-based pitching staff, show no fear of going "up the ladder" against hitters and don't find themselves trying to paint the inside corners all that often, as their inside percentage to lefties is nearly 100% less than the Pirates (22.09% versus 40.03%). Once again, the Cubs seem to be the hybrid pitching staff here, with the lowest "up in the zone" percentage, but also the lowest inside percentages as well.
Thus, while facing similar opponents over the course of a 162-game season, and despite having noticeably different processes (as outlined in the two infographics above), the Cardinals, Pirates, and Cubs were all able to find an abundance of pitching success in 2015. And that, my friends, is why baseball is so great, and oh so fascinating. Will the pitching staffs switch it up in October or will they stick with what has worked for them all season? Given the time to critically review scouting reports over the past few days, this is definitely something that has been mulled over by Derek Lilliquist, Ray Searage, and Chris Bosio.
Based on who wins tonight, I will likely have more of this type of analysis for tomorrow. Buckle up.