The secret to the Twins' pitching success

Parker Hageman of Twins Daily has a good look at the Minnesota Twins and how their pitching staff has managed to reduce its runs allowed from 4.80 runs per game in 2014 to 4.06 in 2015 without a hike in strikeout rate or a significant change in home runs allowed.

Hageman writes:

"It is still perplexing as to how the Twins are accomplishing this feat. True, the outfield defense is noticeably better and more balls in play are being converted to outs but other indicators, like strikeout rates, are worse. The Twins’ pitchers are outperforming their fielding independent expectations by a wide margin. According to xFIP, a statistic that calculates what a pitcher’s expected ERA should be at based on grounders induced, strikeouts gotten and home runs avoided, the Twins should be hovering near the bottom of the league in terms of runs allowed. However, their overall ERA has been significantly better."

Hageman gives a lot of the credit to new pitching coach Neil Allen, who had been the Triple-A pitching coach for the Tampa Bay Rays from 2007-14. Allen has brought some of the wisdom he learned from the sabermetrics-minded Rays:

"What the Rays discovered is that not only is the changeup effective in same-sided circumstances, but the changeup is also potent when thrown consecutively. From 2009 to 2014, the Rays threw the most changeups, but they also threw the highest number of changeups after changeups. And when the Rays pitchers doubled up on changeups -- which they did a MLB-high 32 percent of the time -- they held opponents to a .189 batting average against."

Twins right-handers, in particular, are throwing more same-side changeups. Kyle Gibson, for example, threw his change just 1.5 percent of the time to right-handed batters last year, but is using it 14 percent of the time this season. Overall, the Twins are simply pitching more effectively: Opponents hit .288 against Twins' changeups last year, but are hitting just .204 this year. Hageman points out that the pitchers have been more effective throwing it down in the zone, thus inducing more weak contact.

Can they keep it up? The Twins still have the lowest strikeout rate in the majors, and conventional sabermetrics wisdom says that will eventually come back to bite them, weak contact or not. But the changeup theory at least explains some of the improvement.