Get in the zone, Wade Miley

The other day, while we were watching Wade Miley make his first start of spring training, Andrew brought up an interesting trend he had noticed. Last year, roughly 40% of Miley’s pitches were thrown in the strike zone. That was the seventh lowest mark among qualified starting pitchers and was a career low for him. Batters were still swinging and making contact at similar rates to his career norms, he was just locating pitches in the zone less often. It’s an odd trend so I wanted to dive a little deeper into his granular pitch stats to see if there is anything to be concerned about.

In his first full season in the majors, Miley’s Zone% was 48.3% per PITCHf/x, well above the league average of 45%. It’s dropped consistently, year after year, until it reached its low point last year. A low Zone% isn’t necessarily a bad thing. Last year, both Dallas Keuchel and Zack Greinke had Zone% lower than Miley’s. But when considering the rest of their plate discipline context, both Greinke and Keuchel were able to support a low Zone% by getting batters to chase pitches outside of the zone. Miley might not have the stuff to be able to support a Zone% so low, and it could be one of the reasons his strikeout rate fell four points last year.

To dig a little deeper, I pulled Miley’s granular pitch data from the last four years and compared his Zone% to his called strike rates and his ability to generate whiffs. I wanted to see if it was a particular pitch that was driving his Zone% down or if he was throwing all of his pitches out of the zone more often. I’m presenting a lot of data in a large chart, so bear with me.

A few things immediately stand out. Miley threw both of his fastballs out of the zone more often last year but opposing batters swung and missed less often on both pitches. Fastballs aren't generally used to fool batters so locating them out of the zone may have led to the drop in whiff rate.

He also started throwing his changeup and curveball more often at the expense of his sinker and slider. Not only was he using his changeup more often, he was changing the way he used it. He went from locating his changeup in the zone around half the time to just over a third of the time, and the called strike rate for that pitch dropped precipitously as a result. Just look at how the heat map for his changeup changes between 2014 and 2015:

The foci of these two heat maps is generally in the same area, but Miley started to bury his changeup down and away against right-handed batters. Elevated changeups are generally a bad idea so this adjustment was probably made to help him keep the ball in the yard while pitching in Fenway Park.

Based on the data available, it certainly seems like Miley changed his approach while pitching in Boston. He was able mitigate some of the home run problems he had shown in Arizona, but his strikeout rate took a step back after a promising leap forward in 2014. Now that he’s pitching in the friendly confines of Safeco Field, I wonder if he’ll adjust his approach once again. The additional called strikes he was generating when he was locating his changeup in the zone weren’t insignificant, but he’s able to generate enough whiffs with the pitch that it shouldn’t be a concern. His offspeed pitches are all average to above average offerings and utilizing his changeup more often will probably help him leverage his entire arsenal better.

More concerning was the relative ineffectiveness of his fastballs last year. It could be a one-year blip since the pitches have been so good in the past, but it limits his upside if he isn’t able to get batters to chase these pitches. Ultimately, Miley will go as far as his fastballs will take him. Throwing them in the zone more often—like he was earlier in his career—could be a recipe for success. Luckily, he's got a little bit more room in the outfield to play with if he wanted to start challenging hitters with his heater again.