Joakim Soria has been nothing short of a dominant presence the last three years in the Royals bullpen.  Between 2008 and 2010, Soria saved 115 games, was striking out 10 per 9 innings, had a 4.04 K/BB ratio, and an ERA+ of 236.  There were very few (if any) relievers that matched his production over the course of those three seasons.  But this year, something is wrong. 

Something is very, very, very wrong.

The first thing that jumped out to me is his pitch selection.

Soria is throwing his cutter almost 58% of the time, and fastballs altogether he is throwing 80.7% of the time this season.  This may be a product of a small sample size; according to FanGraphs, he has averaged between 66.4%-74.6% of FF/FC in his pitch selection the previous four seasons (FanGraphs has Soria throwing an FC exclusively last season, and has him throwing a normal FF the previous three years).  This year, Soria has been charted as throwing both pitches.

The one large variance between this season and last is the number of off-speed pitches he is throwing this season.  Due to his fastball numbers being up, his off-speed pitches will obviously go down, and they are down across the board:

Last season, Soria moved away from his curveball and utilized his slider more than he ever had before.  He also had his highest fastball percentage for a complete season, and his changeup was also utilized less than in year's past.  This year, the numbers are down across the board on his off-speed pitch selection, but the curveball is the one that has almost disappeared from his repertoire.  A pitch that was a staple of his pitch selection his first three seasons was cut in half last year, and has taken another nose dive this season.  You could draw a couple different conclusions:

1. Different catcher making different pitch selections:  His first three seasons, he pitched to John Buck/Miguel Olivo (with a sprinkle of Jason LaRue).  Last season, it was Jason Kendall (with a smattering of Brayan Pena).  This year, it is Matt Treanor and Brayan Pena.  From watching games, I would argue that Pena puts down the sign for the curveball a majority of the time it has been thrown this season.  He has thrown it 11 times this season.  I would bet that Pena has been behind the plate a good majority of the time he has thrown it.
2. An injury has led him to back off of throwing off-speed pitches as much:  His off-speed totals for his five seasons are:

This may not be true, due to 2009, when he had that "injured but not injured so the other team will be afraid of him" period, and considering he threw his highest off-speed percentage of his career.  What can be said is that he has steadily increased the amount of FF/FC he is throwing since 2009, from a career-low in 2009 and jumping to a career-high a season later, which he is on pace to set a new high this season.

Superficially, this all seems like a reasonable explanation, but then I dug a little deeper.  The next thing that caught my eye was the Velo, movement and spin on his pitches this year compared to previous seasons:

Pitchfx from 2011:

Pitchfx from 2010:

Pitchfx from 2009:

The easiest thing to see is that his velocity has been down this season.  But more than that, the vertical and horizontal movement on his pitches is drastically different this year than it was the previous two seasons.  Pitchers can get by with a minor variance in velocity, but the movement on some of his pitches (notably, his FF, FC, CH, and SL, the pitches he is using over 95% of the time) are nowhere near what they were in 2010 and 2009.  The spin angle and spin rate are also down, most notably on his fastball this season.  He literally has almost no horizontal movement on a pitch that is being classified as a cutter (0.1).

What this means is that his pitches are flatter and easier to hit.  On top of this, they do not have the same spin that they have in years past, making them easier for the hitter to pick up on what is being thrown.  Combined into this is the fact that he is throwing more fastballs than ever, and the pitch he has thrown the most often (FC) has almost no horizontal movement to it (the movement on his FF is not much better either, at -1.34).

Coupled with all of this data is his stats for the season.  His WHIP, BB/9, and H/9 are the highest of his career, while his K/9 K/BB ratio are the lowest:

Interestingly, according to xFIP, he is actually been a little lucky this season, although I assume this will normalize further, since these statistics do not involve his 5/24/11 appearance.

So, what conclusions can we draw from this wealth of data?  The most obvious ones seem to be that:

1. His control is way off.
2. His velocity is down.
3. The movement on his pitches is a shadow of what it used to be.

And here is the last thing I noticed: his release point

2011

via i.imgur.com

2010

via i.imgur.com

From the looks of these two graphs, it would appear that Soria is short-arming his pitches a little, not getting the full extension needed to maximize their effectiveness.  Here it is isolated on his FC pitch:

2011

via i.imgur.com

2010

via i.imgur.com

It may not be the greatest difference in the world, but has made a huge difference in the quality of his pitches

via pitchfx.texasleaguers.com

2010

via pitchfx.texasleaguers.com

So what does all this mean?  I am still unsure.  It may be a mechanical issue, where a minor adjustment may help him to get extended and get "on top" of his pitches more.  This would increase his spin, movement, and velocity.

On the other hand, the stark decrease in the movement on his pitches, coupled with what may be him short-arming his throws, are pretty good indicators that he either has an injury, or his body is protecting itself from injury, or protecting itself from being injured further.  There is a possibility that it may be an injury that he hasn't detected yet, or hasn't noticed, but his body, on a physiological level, is working against him to protect itself.

No matter what, though, there is definitely something off about Soria this year.

All information from FanGraphs, Baseball Reference, Brooks Baseball, and TexasLeaguers.