It is no secret that the stock of Zach Duke has plummeted in the past two years. In a 2004 season split between High-A and Double-A, the 21-year-old went 15-6 with a 1.46 ERA and a 0.97 WHIP. Duke also struck out 142 and walked 30 in 148.1 innings. He began 2005 at Triple-A Indianapolis, and was obviously an important piece of the Pirates’ future. He did nothing to slow his progress in Indy, going 12-3 with a 2.92 ERA and a 1.21 WHIP. On July 2, 2005, he made his Major League debut in Milwaukee. He won his first six decisions, and finished the season 8-2 with a 1.81 ERA and a 1.20 WHIP. Duke regressed in 2006, posting an ERA of 4.47 and a WHIP of 1.50. In 2007, the wheels totally fell off. He went 3-8 with a 5.53 ERA, and allowed opposing batters to post a ridiculous .359/.394/.547 line. He also missed a large chunk of time due to an arm injury.
As the 2008 season approaches, Duke has gone from a rookie phenom to a huge question mark. Management recently stated that he will start the season in the Pirates’ rotation, but his performance this season may determine whether he has a legitimate future in Major League Baseball.
So what went wrong with Zach Duke? I can think of a few possibilities, and I plan to find the answer. It is possible that his approach is flawed. Maybe he is not throwing inside often enough, or not mixing his pitches effectively. Another alternative is that his mechanics are unsound. I am not a pitching expert, so this will be difficult to determine. Other possibilities that will be complicated to identify include Duke tipping his pitches and injury issues. Finally, Duke just might not have the stuff to compete at the highest level. It is reasonable that he could have dominated the minors with good control and an intelligent approach, and started well with the Pirates before scouting reports flooded opposing clubhouses. Now that there is a book on him, he may just not have the talent to produce.
My goal is to find some measurable difference between Zach Duke in 2005 and Zach Duke in 2007. I plan to look at a few games from each of the past three seasons and analyze Duke’s performance. I will definitely look at his final two starts in 2007, as those games have PITCHf/x data available. I will also watch other games from earlier in the season, and do the same for past seasons. I hope to finish this study before the regular season begins on March 31. More importantly, I hope to find some evidence that Duke could possibly return to his 2005 form.