It is no secret that Dave Duncan is a huge fan of his pitching staff getting groundballs. He’s made a career out of taking discarded pitchers and turning them into useful parts by convincing them to get hitters to pound the ball in the dirt. As Steve Sommer showed a few weeks ago, there is a quantifiable “Duncan Effect”, where pitchers under his tutelage see a significant up tick in their GB%.
The newest member of the Fixed By Dave Duncan club is Brad Penny. You almost don’t need me to run off the numbers, as the story is so predictable. In his first four starts for St. Louis, he’s running a 53.4% GB%, which would be a career high. He’s followed the Joel Pineiro path to success by pounding the strike zone, issuing walks to just 3 of the 109 batters he’s faced this year. The groundballs and strikes combo is working like a charm, and Penny looks to be well on his way to finding career revival, thanks to Duncan’s teachings.
However, while the results are reminiscent of Pineiro’s conversion, the process is entirely different. Last year, Duncan got Pineiro to reduce the frequency with which he threw his off-speed stuff and rely heavily on his sinker, taking his fastball percentage from 58% to 71%. Penny has done the exact opposite; he threw 71 percent fastballs last year, but Duncan has him down to 51 percent this season.
Instead of his fastball, Penny has added a new pitch, a splitter (Pitch F/x calls it a change-up) that is averaging 89 MPH and has been devastatingly effective so far this year. You can see it as the big yellow blob in the first chart below, and see how this is a pitch he just wasn’t throwing last year in the graph of a game from last April below that.
His splitter has been +4.3 runs above average so far, making it one of the best pitches in baseball to date. So it’s not just a trick pitch, but an actual viable weapon. And Duncan apparently taught Penny how to throw it in a month.
For all the talk about how great Leo Mazzone was, Duncan is a guy who we have tangible evidence of his philosophies changing how guys pitch, and seeing dramatic differences in results. If you’re ever going to put a pitching coach in the Hall of Fame, it should probably be this guy. What he’s done over his career is nothing short of amazing.
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