Despite being the proud of owner of a fastball that could often challenge radar guns for accurate readings, for much of his career, A.J. Burnett has been surprisingly ineffective with his seemingly impressive mid to upper-90s heat. For instance, while with the Blue Jays from 2006-2008, Burnett’s fastball was, in total, 1.8 runs below average (-4.1 in ’06, +8.2 in ’07, -5.9 in ’08). In 2009, the lanky starter actually posted his worst fastball value mark ever, as the offering, which generally clocked in at 94.2 mph, was 13 runs below average. In the American League, only James Shields (-13.2) and Carl Pavano (-23.6) were worse, and their fastballs were significantly slower than Burnett’s. If one considers that Burnett is essentially a fastball-curveball pitcher, then this becomes an even greater problem.
But how, exactly, does Burnett manage to be so unproductive with a fastball that most pitchers would die for? According to pitch f/x data from a year ago, the movement on his fastball was solid and, of course, the velocity he can wield is above average. Thus, there is little there to indicate a flaw. Perhaps, then, the problem is not with Burnett’s fastball and, instead, the underlying issue rests on what the pie-loving right-hander is not throwing—his changeup.
In 2009, Burnett threw his changeup just 3.1% of the time. This was actually the lowest percentage of any starter in the American League with at least 180 innings under their belt. Though the best items in his tool belt are his gas and his hammer, utilizing the changeup in a way that matched his career average (5.7%) might have helped the 33-year old achieve greater success with his fastball. I say this because, based on historical pitch value data, Burnett’s best seasons with the fastball also featured an uptick in changeup employment. For instance, in 2007, Burnett’s fastball was 8.2 runs above average as he threw the change 7.1% of the time. Further, in 2005, Burnett’s fastball was 7.4 runs above average and 9.9% of his pitches were changeups. Basically, in the years Burnett utilized his changeup more often, his fastball’s efficacy increased. In the years Burnett threw his changeup less – 3.1% in 2009 (wFB of -13.0), 5.0% in 2008 (wFB of -5.9), and 4.2% in 2006 (wFB of -4.1) – his fastball’s efficacy was hindered. While I cannot prove a direct relationship between the two, it does not seem entirely far-fetched to link his fastball to his changeup, as the fastball and changeup are often dependent upon one another in order to be successful. In fact, it is the only noticeable correlation I can extract from the pitch value data (his use of the curve and slider have not varied much annually).
In 2010, I think we might see Burnett go to his changeup more often (it will be interesting to see how much Jorge Posada or Francisco Cervelli might call for it as compared to Jose Molina), as it will likely help setup his other pitches and increase the overall effectiveness of his fastball. Given the available data, it seems like a constructive idea.
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