Revisiting the fastball of Shelby Miller

Back in January, I looked at the numbers behind Shelby Miller's fastball during his rookie season. In short, it was one of the best fastballs in the league, and he threw it at a very high percentage. He rode it to a third place finish in NL Rookie of the Year voting. Well, unfortunately for the Cardinals, his fastball just has not been the same since the first half last season. For this post, I will simply look at his fastball characteristics instead of results (i.e. BAA, ISO, LD%, etc.). The results are easy to find, but they really don't help us in determining the issues. Well, in my opinion, this chart paints a pretty clear picture:

Both Miller's fastball usage and velocity were relatively steady among the three time frames included in the chart. However, that's really where the similarities end. His fastball averaged an impressive 5.04 inches of horizontal movement (tailing action) in the first half last season. In the second half, it decreased by nearly an inch to 4.16 inches. So far this season, it has decreased even more to an average of 3.66 inches. To put this in perspective his horizontal movement dipped down into the 3's in just six (of 31) starts last season. Now, a horizontal movement in the mid 3's is his average. This is obviously troubling, and yet, it is only the start of his current fastball issues.

A 94-95 MPH fastball is a nice weapon to have, but given the amount of power arms in the league today, it really isn't anything special, especially when hitters are facing it the second or third time through the order. A 94-95 MPH fastball, thrown 70+% of the time, with considerably less horizontal movement than the past, is essentially a big league hitter's dream. The hitter can "guess" fastball, and three out of every four times, he will be correct. He can read the fastball out of Shelby's hand and know a general location of the pitch because it's not tailing nearly as much as it was last season. Making solid contact on Miller's fastball was tough last season, but it is much easier now that it is moving less.

To compound on his decreased horizontal movement, Miller's fastball locations are pretty miserable this season. He is grooving 8.73% of his fastballs in 2014. BrooksBaseball classifies a "grooved pitch" as one that crosses the plate right in the heart of the strikezone (aka "smack dab in the middle"). Thus, if Shelby throws roughly 70 fastballs a game, this percentage means that six of them will be right down the middle. These are six very real chances for the opposing hitter to deposit a home run into the seats. I don't know about you, but that doesn't give me very much confidence going forward.

Finally, his overall fastball location needs a whole lot of work. His location percentages remained pretty steady over the course of 2013, but this has not been the case so far in 2014. Over half (54.5%) of his fastballs have been in the middle or upper zones. These are not the well-placed "up and away" zone either. Instead, these include the meaty "middle-up" and "up and in" zones. Only 13.23% of his fastballs have been down in the zone—nearly a 10% decrease from the second half of 2013. Miller obviously cannot completely abandon going up in the zone. He is already a somewhat one-dimensional pitcher, so be able to locate down-up-middle is absolutely necessary for prolonged success. Plus, he had ample success up in the zone last season, but now, with less movement on the pitch, it really is in his best interest to increase his fastball percentage down in the zone.

The obvious fix to his problems would be to miraculously regain the horizontal movement he had at the beginning of last season. However, it just is not that easy. Are his pitching mechanics different from the first half last season? Is he gripping his fastball slightly differently? Is he hurt? Should he try taking a little velocity off his fastball in hopes of regaining some more horizontal movement? I don't have an answer for any of these questions, but one thing I do know, I would really like to see Miller live down in the zone as he attempts to figure out what's going on with his fastball. Then again, given his 14.2 BB%, does he even have the control to consistently know where his pitches are going?

As usual, credit to BrooksBaseball for the data used in this post, especially this awesome new feature.