Charting the improvements of Mike Pelfrey

When Mark Twain's cousin was sick in London and Twain went to visit, rumors began to circulate that it was actually Twain who was ill and who had allegedly died. Of course the wasn't the case. "The report of my illness grew out of his illness," Twain had said. "The report of my death was an exaggeration."

For Mike Pelfrey these last couple of years there has been no cousin, no evil Twin - no pun intended, no exaggeration of how cooked his arm appeared to be. In December 2012 the Twins took a gamble on a guy recovering from Tommy John surgery, hoping the 4.11 FIP he'd earned through the previous five years would pay off at some point over a relatively inexpensive two-year contract. It didn't. So the Twins offered him another contract, which nobody understood.

Except, perhaps, the Twins themselves. Lambasted from all sides for a $5.5 million dollar contract on a guy who had posted a 5.56 ERA in his initial two-year deal in Minnesota, the organization continued to place faith in a down on his luck right-hander who, ultimately, broke camp with the club as the team's fifth starter thanks to Ervin Santana. All he's done since is give Minnesota 11 starts of 2.28 ERA baseball, racking up 0.8 fWAR and the third-lowest mark in all of baseball for the percentage of balls considered "hard-hit."

Avoiding well-struck batted balls is a skill. Quantifications are ongoing, but for those pitchers who continued to find success in spite of not missing bats, they weren't all just lucky or good at hitting their spots. Being able to change speeds and line of sight are critical. Generating movement, regardless of whether or not a batter swings and misses, will go a long way towards creating an effective and successful pitcher.

This is what's happened to Pelfrey in 2015. His swinging strike rate of 5.6% is disturbingly distant from the league average of 9.7%. He's roughly league average when it comes to first-pitch strikes. The walk rate of 6.9% is good, but it's within sight of the league average rate of 7.6%. Those are the type of numbers where, in most circumstances, you'd expect a hard fall sooner rather than later; I'm not convinced that will happen, at least not to the implosion-level event we'd have been waiting for from the 2013 or 2014 version of Mike Pelfrey.

Here are three very telling Pelfrey charts, courtesy of Brooks Baseball. We're looking at charts from Pelfrey's most recent start, which was as good as we've seen him in Minnesota, and then the only start from 2014 that saw him throw more than 100 pitches.

Pitch speed: June 7 2015 vs April 4 2014

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Velocity is one of the common themes when talking about Pelfrey's renaissance. On the left are his velocity points for his start on Sunday, and on the right is his start from April 4 of last year. In 2014 not only is his tail off in pitch speed evident, but he wasn't varying speeds either. Five pitches came in between 86 and 87.5 mph and the rest were 91 mph-plus. In 2015 not only does the velocity hold, not only is the upper end of the velocity range higher, not only is Pelfrey mixing his speeds with aplomb, but there's a massive gap - a full five miles per hour worth - where there was just nothing. Being able to do that, much less turning those two speed bands into four or five pitches that a batter needs to be ready for, is a very good sign.

Horizontal movement vs Vertical movement: June 7 2015 vs April 4 2014

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Once again you can see how, on the right (2014), everything is in virtually the same area. For a guy like Mike Pelfrey, who needs his pitches to sink so that he can induce ground balls, he just wasn't getting it. There also wasn't much horizontal movement. When there isn't much movement, a guy is going to get hit hard.

On the left side, meanwhile, you once again see a clear differentiation between sink and horizontal movement. Pelfrey kept the ball down and was able to set hitters up by changing line of sight.

Spin vs Rotation: June 7 2015 vs April 4 2014

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Spin and rotation of a baseball is what helps to generate - or dampen - movement on a pitch. On the right, all of Pelfrey's pitches - regardless of speed or classification - had exactly the same spin. Most of his pitches had rotation between 1,600 and 2,100 RPM. By contrast, in 2015 the spin axis was far more differentiated and that big cluster of pitches saw between 1,800 and 2,200 RPM; the lower end saw pitches getting as low as 300 RPM.

The purpose of these three charts isn't to point out how different Pelfrey's pitches look between a good start and a bad one. The purpose is to show what's been happening to his pitches this year in regards to movement and, as a result, show why he's been the successful pitcher we've seen over 11 starts this year.

What does all of that new movement mean? It means hitters are wondering where Pelfrey's arsenal came from. It means that hitters are being fooled by later movement and as a result swinging at 75% of Pelfrey's pitches out of the strikezone. They're still not swinging and missing but that type of contact works in the pitcher's favor. It means that splitter and sinking fastball, and four-seam fastball for that matter, are helping to keep the ball on the ground thanks to break later it the life of each pitch; his 55.2% ground ball rate is a career best, hits 25% fly ball rate is the lowest of his career, and only 5.7% of fly balls have ended up as home runs so far.

Success in baseball is rarely something that can be boiled down to a single statistic or player trait, and that's as true for Mike Pelfrey in 2015 as it is for any other player that's had a good season. His pitch selection is drastically different than what we've seen him do in a Twins uniform previously, but is he mixing up his repertoire because he's commanding his pitches better or has the confidence grown as a result of early success in switching things up? It scarcely matters. The sinker (53.8% of pitches) is working, use of the four-seamer (14.5%) is down in spite of the velocity spike and how effective its been, and the splitter is getting more attention than Pelfrey's ever given it before (16.8%).

What does all of this mean for Pelfrey in terms of his contributions to the Twins going forward? As long as Pelfrey continues to generate the movement he's been generating, he's going to continue to have success. I couldn't have imagined saying this six weeks ago much less six months ago, but if Minnesota wants to win as many games as possible in 2015 it looks like they'll need other ways to fit younger arms into the rotation.