Drew Storen has been optioned to the Class AAA Syracuse Chiefs. Just last week I had predicted he would see some improvement in his pitching line over the final months. What I hadn’t observed was the breakdown in Storen’s mechanics that led to the demotion. Changes in Storen’s pitch movement and speed have emerged, along with some different approaches to mixing his pitches, that can be at least in part attributed to the mechanical issues. If the change in approach is related to feeling a need to compensate for the other issues, we should see some return to prior approach when he returns.

The Natstradamus Blog took a look at Storen’s pitch mix and results this weekend, featuring the data I help publish at Brooksbaseball.net. The analysis had two important (and related) observations and one suggestion. Storen’s slider had lost about 2 mph and, to summarize the blog, didn’t have the same bite as it did in 2012. His change-up and fastball remained at a similar level of effectiveness, which is reflected in the suggestion to focus on those two pitches while in the International League.

This piqued my curiosity so I’ve taken a closer look at Storen’s fastball — or fastballs — and change-up. Storen is already throwing more change-ups. In 2012 he increased the frequency he threw them to left-handed hitters to nearly 15 percent from less than 5 percent the year before. This season he’s up to more than 20 percent change-ups when the platoon is against him. Storen’s even throwing change-ups to right-handed hitters now, from a once in a blue moon to once in every 10 pitches. These extra change-ups have eaten into Storen’s fastball usage. His slider usage is up in 2013, despite no longer being the blowaway pitch it was a season ago.

Storen’s four-seam fastball has been used less this year than any prior season of his career. His two-seam fastball had been marching upward until it became his favorite pitch in 2012. Now he’s throwing more sliders than two-seamers, an almost equal (but lesser) amount of four-seamers and, last but not least, the emerging changeup. As noted above, Storen lost 2 mph off his slider. His fastballs are both down a full mph after holding steady for almost four years.

So what have we got? A less biting slider, a drop in fastball usage and velocity, increased slider and change-up usage. And some sudden changes in the last week.

When Milwaukee and San Diego visited, Storen threw sliders that moved about 7 or 8 inches (or more) toward his glove side. Against Pittsburgh and New York it was down below 3 inches of movement. When this all started, on July 20, he threw four-seam fastballs that looked more like cutters.

It was reported that Storen had been struggling with his mechanics all season.

In the last outing before he was optioned to Class AAA Syracuse, Storen, who has battled and tinkered with his mechanics all season, abandoned his traditional stiff front leg delivery for an older version of his delivery.

There are more specifics in Wagner’s post, but the general conclusion we can draw is Storen has not been comfortable with his delivery. This could certainly explain the lack of velocity in general and the weaker bite on the slider. It also appears Storen has been making non-subtle changes since the all-star break that have had a negative impact on his performance. Like it or not, the place for that is Syracuse. Hopefully it won’t be long before he’s back on track and looking like the Storen of recent memory. It will also be interesting to see if those changes in pitch mix persist.

Harry Pavlidis is the founder of Pitch Info. Follow him on Twitter: @harrypav.