Should the Astros be concerned about Wandy Rodriguez?

In regards to Wandy Rodriguez, it's a good thing I am not a GM. I would have Wandy locked into a longterm deal with the Astros before 2009 ever closed out. There was nothing not to like about him. His raw numbers were dazzling (3.02 ERA, career high K:BB, ate innings like it was going they were going the way the McRib) and his true talent numbers seemed to indicated that it was no fluke (3.63 xFIP). I would be getting blasted by Richard Justice right now, though, as Wandy's raw numbers are tanking (5.60 ERA, depressed K:BB) and his true talent numbers indicate that there is some bad luck involved, but enough to make anyone feel much better (4.48 xFIP).

Why is that? What did we miss? And should expect from Wandy Rodriguez's once Wandilicious left arm?

The first place I'll start is with two numbers that I have glossed over until I went to start researching this piece:

Am I only the one who didn't pay attention that jump? I wrote two pieces on Bud Norris' right arm, but I honestly did not even consider that Wandy might be facing some ill effects after his first 200 IP season coming on the heels of an nagging-type injury filled 2008. I will never cease to amaze myself with my own obtuseness.

My introspective neuroses aside, that kind of spike in innings pitched is certainly something should raise an immediate red flag. Looking at raw innings pitched, though, is a very blunt diagnostic tool. IP do not account for context like pitches per inning, batters faced, pitches from the stretch, fatigue, or pitch selection, etc. We can gain some context by looking to another great starting place, Baseball Prospectus' Pitcher Abuse Points. Wandy ranked 23rd in overall PAP accrued, had eight Category Three starts, and one Category Four. Mildly stressful according to the PAP, but nothing to be concerned with—in isolation.

We are not looking at Wandy in isolation, though. We already know that Wandy tossed nearly seventy MLB innings more than he did in 2008, and that he tossed nearly twenty innings more than he had ever before in his career. The last stone we need to turn over is batters faced. In 2008, Wandy faced 23.5 batters per start and in 2009, 25.73. So we have enough to suggest that Wandy's inning increase was coupled with an uptick in stress over the previous year. No single variable is concerning, but the combination of them should certainly raise an eyebrow or two.

The important aspect of this thread of analysis is how is this manifesting itself in Wandy's 2010. Thanks to the much missed Josh Kalk, now in the Rays front office, we can gain some insight. This is thanks to a seminal piece of pitch/fx analysis on pitching injuries published back in early 2009. In that piece, which goes way beyond my pay grade in terms of number crunching, Kalk loosely determined the following through neural network analysis:

...the most important variable is speed followed by vertical movement, horizontal movement, vertical release point and then horizontal release point. Previously, we learned that even after throwing a lot of pitches, pitchers don't lose a lot of speed on their fastballs, so it isn't too surprising that if a pitcher has lost a good deal of speed on any pitch, something might be wrong…Vertical movement was the second most important and, if you combine horizontal movement, total movement is actually more important than speed. Movement here is created entirely by spin and drag, so if a pitcher isn't quite right it is very hard to get the proper spin on the ball. Vertical movement is likely more important than horizontal because most of the spin applied is backspin (fastball) or front spin (curveball) which makes the move up or down.

So now we have to look to the pitch/fx data to determine whether or not Wandy is lacking in these crucial areas. The caveat that has to immediately be applied here is that Kalk's pitch/fx database went through rigorous corrections to neutralize park-to-park effects. I am utilizing FanGraphs' data and I am not sure of the corrections—if any—that are made. However, it is what I have to work with and it will have to suffice.

The raw data, including previous years, can be viewed here. I feel as though the 2009 to 2010 comparison is the one we should be focused on and so I have provided the year-to-year differences. With Kalk's analysis in mind, we should be leery of decreases in speed, vertical movement, and horizontal break.

Speed: Wandy's two fastballs are anomalous to me. His four seam fastball has clearly lost a step this year, yet he apparently throws his two seamer faster anyways? I am not a pitching guru, so I can't tell whether the grip of the ball is generating a different kind of a spin that could explain the discordant results Wandy has been getting, but the one thing we should definitely note is that Wandy's four seam fast ball has lost speed. His curve ball is also unsettling, having lost over a mile per hour year-to-year. His change up remains essentially unchanged year-to-year. So, Wandy's four seamer and curveball are scary while his change up and two seamer are not.

Vertical movement: Wandy has lost just a titch of vertical break on his four seam fastball and his two seamer has lost an inch and half. However, I do not know whether we should interpret the loss on the two seamer as menacing as this could be an intentional ploy on Wandy's part to induce more ground balls. What is troublesome is Wandy's curveball which has actually gained inch in drop. As Kalk points out, vertical movement is important because it is determined by the spin a pitcher is generating and for the curveball to drop an extra inch means that Wandy isn't getting as much spin on the pitch as he did in 2009. Counterintuitively, though, extra drop, or 12-6 break, correlates with greater success and Wandy's curveball has not been successful this year—at all. Perhaps, then, Wandy's curve has more "hump" in it. This digression aside, the change in vertical movement concerns me as it is coupled with a loss in speed. We also see a change in the vertical break with Wandy's change up of about an inch, so across the board, Wandy's pitches are behaving differently along the y-axis in 2010.

Horizontal movement: The change in Wandy's horizontal movement on his four seam fastball scares me more than any other year-to-year change. That is a huge swing and, to me, seems to indicate something is definitely off with Wandy's delivery; be it injury concerns, fatigue, or mechanical tweaks. Wandy's change up also has lost a significant amount of horizontal break as well. Yet, his curveball has identical horizontal break and his two seamer has actually gained movement along the x-axis.

What do we make of all of this? Well, we have a pitcher who saw a significant jump in innings pitched coming off a year in which he dealt with minor muscle injuries. Those innings pitched were accompanied by measurable factors that indicate that those innings were potentially stressful innings. Then, when we look at known correlates with injury via pitch/fx data, that pitcher's four seam fastball and curveball display alarming trends towards fatigue/injury manifestation, but two other pitchers that are relatively neutral...but those two alarming pitches are the main weapons in the pitcher's arsenal.

There seems to be enough on the table to make me think that Wandy needs to have a start or two skipped. If not because injury has already set in, than to reduce fatigue—which Wandy's pitch/fx data indicates he is suffering from. Even though the rotation is already lacking depth with Bud Norris recovering in Round Rock, we know that Wandy's near replacement level performance this year wouldn't be hard to replace with in house options already toiling in the minors. I think the prudent move would be to allow Wandy to hopefully recover by going this route. Swapping out replacement level for slightly above replacement level performance in the hopes that well above replacement is spit on the other side seems fairly risk neutral.

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