In case you haven't been watching baseball much this year, here's a quick recap of the Twins' season: it's not good. As of yesterday, the Twins were a lowly 64-90, dueling the Cleveland Indians for the title of "Worst AL Central -- and by default, American League -- Team." It's a bad, bad scene in the Twin Cities this year. Would you like to know why it's so bad?
I'll tell you, it's because of their pitching. Twins starters have been good for a shocking 2.3 fWAR on the season. Naturally, this is the worst in the majors. By a fair margin. The Padres starters have a combined fWAR of 3.8, but they also have an ERA of 4.33, nearly a full run lower than the Twins. In practice, they've given up far fewer earned runs per nine innings.
Basically, if you found a bunch of replacement-level starting pitchers in Triple-A, or Japan, or Mexico or pretty much anywhere else, they'd probably be about two wins worse than the guys the Twins ran out there this season. But only two wins.
By the way, that 2.3 fWAR? It comes courtesy of Scott Diamond, who has a 2.4 fWAR on the season. Diamond is responsible for literally all of the surplus fWAR that the team's racked up. That's awful. Their ERA is second-worst to the Rockies' ... and the Rockies pitchers throw half of their games at Coors Field.
Sometimes, words aren't as expressive as the numbers. Here are the woeful, awful numbers.
Twins Starting Pitchers (five or more starts)
* rWAR is for all innings pitched, combined starting and relieving, because I can't find it for just starting sorry everyone
The Twins probably don't have the worst starting rotation of all time. That'd be quite a surprise if they did. I'd be willing to bet that they wouldn't have the worst starting rotation even in the last ten years. (By the way, you should not bet against me. I've run the data.) Sure enough, they aren't the worst in the last ten seasons. They're the third-worst. Only the '09 Brewers and '07 Nationals posted a worse fWAR among their starting pitching staffs since 2003. Ick.
When doing this research, I wanted to reach out and examine how much of the Twins' lack of success might have had something to do with their home stadium: Target Field. After all, if you look at the disparity between ERA and FIP for Twins starters - they at least tend to have an FIP (5.02) that outperforms their ERA (5.52). Perhaps that could have something to do with playing in a hitters' park? Since Target Field only opened in 2010, let's pull what little data we have, based on three different park factors.
Park Factors for Target Field
Well, even I can spot an outlier here. All numbers below 100 (or 1.000 in ESPN's case) mean that a park benefits the pitcher, rather than the hitter. All numbers above 100 (or 1.000) mean that the hitter has the advantage.
By history and by acclimation, Target Field has been considered a slight pitchers' park since it was built. According to Baseball-Reference and FanGraphs, the stats back up that assertion. And prior to 2012, so did ESPN's.
B-R and FG adjust their park factors based on multi-season samples, but ESPN does not. ESPN's park factor is only based on what has happened in 2012.
Simply put, one of two things is likely. The first is that something has changed about Target Field, and it has been transformed from a slight pitchers' park to a heavy hitters' haven. Since there's no record I can find of massive changes to the way the park operates, like adjustments to fences, lighting, etc., I think that's a non-starter.*
* Note: You deserved that bad pun, Minnesota. Step up your game.
The other -- far more likely -- thing that could have happened, is that MInnesota's pitching staff has been so awful this season, that it has skewed the park factor data for Target Field in ESPN's methodology. Things are so bad in Minny, that the Twins' rotation has broken the (already a bit busted) ESPN Park Factors.
By any measurement, the Twins have had a terrible run of starting pitching this season. If they were to keep this up for another season, they may just be better off changing their name to the Tlosses?