A Hypothesis on Shelby Miller’s Struggles


Let’s talk Shelby Miller for a minute.

While thinking through possible reasons for his lack of success this season, something hit me like a bolt of lightning, and no, it wasn’t his current brutal WHIP of 1.482 which pretty much tells you what you need to know about what’s went wrong for him this year. The real question that needs answered is, what has happened to him to post these numbers and why?

One thing that quickly came to mind is simple. He doesn’t ever seem to use his changeup any more.

Now, I’m not saying he has the greatest change in the world, or ever has, but I do remember him mixing it in during his initial call-up in 2012 and then also a little bit in his rookie season that saw him finish 3rd in ROY voting. So, I did a little digging on fangraphs.com just to see if my suspicions were correct.

What happened when I began looking for an answer reinforced what I noticed, and then it revealed much more, causing me to form a hypothesis about what I believe has happened to Miller this season.

In order to fully frame where I’m about to come from I want to jump back to 2012. Miller arrived on the scene after years of hype, and delivered the goods by appearing in six games, starting one, while finishing his cup of coffee with a 1-0 record, 1.32 ERA, a 4:1 K/BB ratio, and a .951 WHIP.

He looked every bit the heir apparent for Chris Carpenter that many fans, myself included, expected to see after waiting oh so long for him to finally grace the mound at Busch Stadium. So, how did he turn in these sterling numbers in 2012?

He did it by mixing his pitches. According to Fangraphs, Miller threw his fastball 69.4% of the time, his curve ball 19.4% of the time, and his changeup 11.2% of the time. The most important part of this mix, however, is that he controlled those pitches very effectively, as evidenced by his .951 WHIP. Yes, it was a limited sample size, but the results were still very, very good and provided a foundation for a belief that much brighter days were ahead.

With a solid handful of outings behind him in 2012, the 2013 season looked promising to say the least. Miller proved 2012 was no fluke by turning in a 2013 season that saw him post a 15 win rookie season behind the strength of a 3.06 ERA, but looking back now there were possibly warning signs that tough times were ahead.

Miller’s K/BB ratio dropped from 4:1 during 2012 to 2.96: 1 in 2013 as his WHIP rose to 1.206, but why? Was it mere regression from a rookie pitcher adjusting to life in the big leagues on a full time basis, or was there something else driving it?

Once again turning to Fangraphs, it looks as though Miller began toying with a cut fastball in 2013, tossing it 4% of the time, but his use of the cutter came at the expense of his changeup, which dropped from 11.2% to 6.3% of the time, and curve ball, 19.4% to 18.4% of the time.

Looking at 2013 in a bubble, Miller’s season could still be considered a success, but now we have everything that has taken place in 2014 to use as further proof that this regression is no coincidence. Miller has upped his usage of the cutter in 2014 to account for 7.2% of his repertoire, and once again, the change (down to 3.3%) and curve (down to 17%) have suffered as a by-product. Couple that with the increased usage of his fastball each year (69.4% in 2012, 71.3% in 2013, and 72.5% in 2014), and quite frankly there just isn’t enough variation of his pitches to keep hitters honest.

Shelby Miller is essentially throwing a fastball of some sort 79.7% of the time, and he’s not pounding the zone with it well enough to get by anymore. His K/BB ratio now sits at 1.3: 1 and that’s just not getting the job done.

Keeping hitters off balance is the key to being a successful pitcher at any level, let alone the highest level in the world where those hitters will make an adjustment and simply disregard an offering that poses no threat to their at bat.

Perhaps the fix that gets Miller back on the right track is as simple as Shelby putting the cutter on the shelf and getting back to using his original assortment of pitches that had him looking like a future Cardinal Ace when he debuted back in 2012.