Neftali Feliz was absolutely dominant last year as a closer. This year... not so much. He currently ranks 13th on the team in pitching WAR, just behind Dave Bush, his K/9 has dropped from 9.22 in 2010 to 6.27 in 2011, his BB/9 has spiked from 2.34 to 4.58, and he has blown 20% of his save opportunities after blowing only 7% last year. How can a pitcher who is throwing the same pitches he threw last year have such different results?

While arguing an admittedly stupid opinion in the postgame thread, I went to look at Fangraphs and their Pitch F/X data on Neftali Feliz. I remembered reading the article "What's Wrong With Neftali Feliz?" by Dave Cameron on Fangraphs and being intrigued by his observation about the loss of some horizontal movement on Feliz's fastball. It was dismissed at the time as SSS, but two months later, the sample size has grown a bit larger. Here's the data:

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Horizontal Movement:

via www.fangraphs.com

Vertical Movement:

via www.fangraphs.com

Neftali Feliz's Fangraphs Page

Looking at his movement charts, there's now enough of a sample size to say that he has lost significant horizontal movement on his fastball (FB). On average, it's showing he has lost a full 2 inches! of H-movement on his FB with no loss in V-movement. While some will point out that because his V-movement is the same as last season's, his H-movement probably shouldn't change, V-movement and H-movement are not necessarily tied together and the consistency of his V-movement between the past two seasons suggests that there may not be a funky error in the Pitch F/X calibration.

Looking at his breaking ball, his curveball/slider (CB/SL) H-movement shows a trend in the positive movement direction, same as his fastball. There could be two possible reasons for this: a. Pitch F/X has been calibrated differently this season, causing a positive direction trend in horizontal-movement for all his pitches or b. Feliz is spinning a tighter breaking ball while losing movement on his fastball. While both his FB and CB/SL show changes in H-movement, the limited number of changeups (CU) he has thrown this year show no change in H-movement from previous years, leading me to believe that the overall trend cannot be blamed on a system-wide error in the Pitch F/X data. Feliz is more than likely getting more H-movement on his breaking ball and less on his fastball.

With Feliz's struggles in the closer role this season and no other obvious reasons for the decline in his numbers, you have to wonder about the effects of his loss in horizontal fastball movement. He has not lost any FB velocity (95.8 average this season vs. 96.3 last) and he's still throwing his fastball at a similar rate (79.5% vs. 82.2%), but because of his heavy reliance on a dominant fastball, any change in movement should have a huge effect on his ability to get batters out. This is shown in the increased amount of contact batters have made on Feliz's pitches this season and the decrease in swinging strikes. The only thing it doesn't fully explain is Feliz's absolutely horrendous splits against RHB this season (0.43 K/BB), while his splits against LHB (4.00 K/BB) are great (even though they still regressed from last season). Those L/R splits are truly baffling. Maybe he's suddenly having an extremely tough time finding the outside corner to RHB?

Another obvious explanation for his drop in performance is that the league is adjusting to him in his second season. This is probably at least partially true, but I don't think it fully explains such a significant drop in his peripherals from last season. If it did explain it, we would have seen evidence of batters beginning to make adjustments last season.

The biggest question I have regarding the large drop in fastball movement is simply, what caused it? The only thing different from last season is that Feliz added a cut-fastball. Not being a pitching expert myself, I'm not sure how that would have any effect on the way a 4-seamer comes out of his hand.

I think we can all agree that something has changed about Feliz's pitching between last season and this season, even if we don't know exactly what it is yet. Whatever the problem is, it's up to people much more knowledgeable about pitching than me to figure it out. Hopefully, we see the 2010 Neftali Feliz back soon.