What’s Left in the Tank for Chicago White Sox Starter James Shields?

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With the team falling fast in the standings after a hot start, the Chicago White Sox made a bold move and acquired a veteran pitcher who was desperate for a change of scenery. Ian York uses PITCHf/x and his unique charts to examine what went wrong in San Diego for new Chicago White Sox starter James Shields, and if there is hope that he can turn it around.

James Shields signed a four-year, $75 million contract with the San Diego Padres in 2015. After four consecutive years as an above-average pitcher with the Tampa Bay Rays (ERA+ of 134 and 109 in 2011 and 2012) and the Kansas City Royals (ERA+ of 131 and 123 in 2013 and 2014), Shields was a sub-average pitcher for the Padres (ERA+ of 94 and 90 in 2015 and 2016).

He was traded to the Chicago White Sox on June 4, 2016 for Erik Johnson and Fernando Tatis Jr. The Padres are also sending Chicago $31 million to help offset the cost of his salary. What are his chances of returning to his 2011-2014 form for the White Sox?

Shields throws a wide range of pitches, with five pitch types roughly evenly mixed: four-seam fastball, sinker, cutter, curve, and changeup. According to Brooks Baseball, his pitch mix hasn’t changed much over the past years:

As his declining results suggest, the effectiveness of his pitches has dropped over the past couple of years. I looked at the total bases per 100 pitches, and the number of balls per 100 pitches, for each of his five most common pitch types. The dotted line on each chart shows the corresponding baseball-wide average.

Even in his better years, none of Shields’s pitches were dramatically better than average. Being able to throw five league-average pitches is valuable enough to get better than league-average results.

Unfortunately for Shields, however, he is showing a number of unpromising trends. His strike rate has dropped for both of his fastballs (four-seam fastball, the top chart, and two-seam fastball or sinker, second from top), as well as his changeup; even though those pitches are not being hit harder than in previous years, he has to throw more of them to get strikes, so the overall results are worse. His cutter’s strike rate hasn’t changed much compared to his effective 2011-2014 period, but that pitch is being hit harder: 14.2 total bases per 100 cutters, significantly worse than the 9.8 TB/100 in his 2011 season, which was still slightly worse than average.

The other trend of concern is Shields’ fastball velocity, which peaked in 2012 and has been dropping steadily since. This chart shows his mean fastball velocity (including both the four-seam fastball and the two-seam fastball, called a “sinker” previously) as the solid line, and the maximum velocity as the shaded region. In 2012, Shields could call on a fastball up to 96.7 mph when he needed to; so far in 2016, his fastest fastball has been just 94.3 mph, and he has averaged just 90.7 mph.

A secondary problem with his declining fastball velocity is the separation between his fastballs and his changeup. Although his average changeup speed has been dropping in step with his fastball, the gap between his average fastball, and his faster changeups, is shrinking.

Aside from the velocity drop, none of these trends are devastating: Shields is still just about a league-average pitcher. One aspect in Shields’s favor has been his durability: He has thrown over 200 innings every season since 2007, and he is roughly on pace to do the same this year. His move from a surprisingly hitter-friendly park in San Diego to one that is fairly pitcher-friendly in Chicago should help his ERA. Considering that San Diego is subsidizing about $31 million of the remaining $57.8 million on Shields’ salary, Chicago may have picked up a cost-efficient third or fourth starter for their rotation, at least for this year. However, if Shields’s trends continue in the same direction, he may not be a great bargain by the end of his contract.


Ian York uses the PITCHf/x to monitor the strike zone, highlights great performances, monitors league-wide trends and tracks the performances of some interesting young hitters.

Follow Ian on Twitter @iayork.

All data compiled from PITCHf/x and Baseball-Reference.com.

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Ian is an immunologist and virologist who lives in Atlanta with his wife and two sons. Most of his time is spent driving his kids to baseball and soccer games, during which he indoctrinates his children on the glories of Pedro Martinez, the many virtues of the Montreal Expos, and other important information.

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