Almost one year ago, I took my initial stab at sabermetrics writing about how the Twins’ fabled philosophy of “pitch to contact” was being stifled by the club’s own inability to field the ball. If you are putting that much faith in your defense, it would make sense that you would have the defensive ability to back up your philosophy. For a while, this was true for the Twins. I am not going to rehash what I already wrote in August of 2015, but if I haven’t summarized myself adequately enough yet, I’ll attempt to do so again: the Twins fostered a philosophy in pitch to contact that relied on their defense, yet from 2010-2015 their defense slowly deteriorated, as did their pitching and overall record. My thought was that if the Twins were able to improve on this sub-par defense, they would be able to bail out their pitching, rather than continue to hamper it. I relied a lot of the idea of fielding-independent pitching, so if you are unaware with that concept, read about it here.
Fast forward to 22 months later, and the Twins have some new captains running the ship. These guys value math, and have started to take a more analytical look at the Twins. The most noticeable difference so far in the Twins’ somewhat surprising season (although as of this posting the team has fallen back to earth somewhat) is their improved defense. To this date, the Twins have the fourth-best defense according to Defensive WAR. Last year, they were the second-worst defense. This idea has already been written about, showing that my prediction nearly two years ago was correct. The whole idea that, on average, a good defense can bail out pitching still holds, and I ran a regression to prove it. On average, a one-unit increase in your FIP-ERA difference increases your defensive rating by 49 points. This is quite the turnaround, showing how valuable a defense can be, and this number, in combination with batting and pitching WAR, can be quantified to show its overall impact on a club’s record. I’ll spare the calculation, but one can see how this improved defense has helped lead the Twins to their surprising start.
Unfortunately, the Twins’ pitching (besides two great starts from Ervin Santana and Jose Berrios) has been awful, so any defensive gains this season have been erased by having the second-worst ERA and FIP in baseball, despite the 13th-best FIP-ERA metric. To this point in the season, the Twins have the same ERA as they did last year, but their FIP-ERA difference was a horrendous -0.52. They have a positive FIP-ERA difference this year at 0.12, showing that their pitching has actually gotten worse from last year to this current season. In some ways, their defense has kept the team above .500. Turns out my prediction was right: improve the defense, and the team will be noticeably better. If the Twins’ pitching would have stayed at the same point as last season, (4.57 FIP), in combination with their FIP-ERA metric, the Twins would be in the top-20 for pitching this season. Unfortunately, the regression of the pitching staff (independent of the defense) has kept the Twins from fully benefiting from their improved defense.
Before I wrap this up, a quick side-note on the Cubs this year. Last season, the Cubs had far and away the best defense in baseball, the best FIP-ERA in baseball, and the best ERA in baseball. This year, as any baseball fan would recognize, the Cubs have been struggling, especially with their pitching. Coincidentally, the Cubs’ pitching this year has dropped to 14th by ERA, along with their defense, which is also ranked 14th. Their FIP-ERA metric is at 13th in baseball, so their regression in defense may be partly to blame for their pitching struggles.
To sum, from 2010-2015 the Twins’ defense deteriorated, leading their pitching staff to do the same based on their pitch-to-contact philosophy. I wrote a year ago that the Twins needed to improve their defense if they wanted to continue this philosophy. They improved their defense, which has fueled a surprising start for the club, and has kept the team from bottoming out with their horrendous pitching staff.
Linear Regression and Plot