Wade Miley, dingers, and upside

Yesterday, the Seattle Mariners traded for left-handed starter Wade Miley. To the great dismay of many, Jerry Dipoto gave up another left-handed starter in Roenis Elias to get Miley (not to mention Carson Smith, and we won’t because that’s a topic for another article). While this may seem like a horizontal move at best and moving backwards at worst, I think the trade raises the floor of the roster and mitigates some of the risk that derailed this team in 2015. It may be hard to see on the surface, but there is some upside to Wade Miley.

During his major league career, Wade Miley has proven himself to be a capable, durable starter who may have some additional upside. He’s averaged 2.5 fWAR and 198 innings per year over the last four years. Those marks are good for 37^th and 15^th, respectively, in all of baseball during that time period. He’s been hurt by both of the stadiums he’s called home. A simplistic assessment would be his home/road splits. For his career, his pitcher slash line has been 4.32/3.70/3.87 at home and 3.61/3.70/3.87 on the road. Most tellingly, his home run rate at home has been 12.1% while just 9.2% on the road.

Moving to Safeco Field will certainly mitigate some of his dinger problem, but if you look closely at his pitch usage, something else pops out. He’s changed his arsenal significantly during his time in the majors leading to some uneven year-to-year performances. But last year, something changed and he was able to lower his home run rate to just 9.2% despite pitching in Fenway Park half the time.

Here’s a chart tracking his pitch usage throughout his career:

In his first full year in the majors, Miley posted a robust 4.1 fWAR on the back of a 3.15 FIP despite a strike out rate of just 17.8%. The next year two years, his walk rate and home run rate inflated leading to identical FIPs of 3.98. His strikeout rate also ballooned in 2014, which matches that spike in slider usage. He was traded to Boston last offseason and saw both his walk rate and home run rate fall. As a Red Sock, he began using his changeup and curveball more often at the expense of his slider and even experimented with a cutter in September.

Historically, his slider has been around league average in its ability to generate whiffs, though it did lose some effectiveness this year. It’s also the pitch that has the highest home run rate in his repertoire. As he used it more often in 2013 and 2014, he gained some velocity on it. That added velocity also flattened the pitch out—between 2012 and 2014, the pitch lost more than 2 inches of vertical movement, even though it gained 4 miles per hour on average.

If he’s going to continue to substitute his slider with another pitch, his changeup is certainly the best option. He was able to generate an above average amount of whiffs with it last year, and increasing its usage as the year went on corresponded with a similar increase in strikeout rate. It induces grounders at an above average rate as well, and most importantly, batters have a tough time hitting out of the park.

Like I did with Joaquin Benoit, I’d like to take a look at Miley’s ability to limit hard contact. Last year, Wade Miley was 60^th in average batted ball velocity with a mark of 87.52 mph, putting him in the top 80% of pitchers in all of baseball. Here are the average exit velocities for each of his pitches:

Miley’s changeup is his best pitch when it comes to limiting hard contact. By all the relevant measures (whiff rate, ground ball rate, exit velocity), it’s his best pitch. I was surprised to see that his slider had the second lowest average exit velocity, right around his overall average. That tells me that when he’s able to command the pitch, it’s fairly effective, but he also doesn’t possess the command to maximize its effectiveness.

I think we can safely say that Wade Miley will be a serviceable number 3 in the Mariners’ rotation for the next few years. Though his peripherals have shifted around from year-to-year, his overall performance has been fairly steady. I'm not sure how anyone could come away thinking Roenis Elias could match Wade Miley in overall performance, especially considering their new circumstances. Like any other pitcher, Miley will benefit from the friendly confines of Safeco Field.

With the changes in his pitch usage, there’s some potential for even greater upside. His strikeout rate might not reach the loft heights of 2014, but his changeup is a real weapon that should help him continue to mitigate his home run problems. Those improvements could drive his FIP as low as 3.60, where it was in the second half of 2015. It would be irresponsible to assume that’s where his new true talent level lies, but his changing arsenal should color our opinion of him. Color me impressed, Wade Miley is much better than many of us assumed.