As a fan of the Yankees in general and of Chien-Ming Wang in particular, it was extremely difficult to watch the demise of the former staff ace play out over the course of the past two years.
Wang started out 2008 strong, winning 6 of his first seven starts. Then he hit a rough patch, working up an ERA of 6.45 over his next six outings before briefly getting back on track just as the second round of interleague play was beginning. Of course, he injured the arch of his foot running the bases after 5 innings of shutout ball in Houston and it was all downhill from there.
When he came back in 2009, he had one of the worst three game stretches possible to begin the season. In just six innings, he gave up 23 runs. Wang had transformed from a dominant sinkerballer to a batting practice pitcher.
What caused this seismic shift?
According to pitch f/x data from FanGraphs (which only dates back to 2007), 73% of the pitches Wang threw in '07 and '08 were sinkers. However, in 2009, only were 57% sinkers. Is that possible? I know it's a small sample size, but it's hard to believe that he would have changed his repertoire that dramatically.
From my read of the data, it seems as though Wang was throwing the same amount of sinkers, but some were so flat that they were being miscategorized as two-seam fastballs. Two-seamers move similarly to sinkers but less downward and more to the right. Lets take a look at the velocity and movement of Wang's versions of those pitches:
In 2009, it appears that Wang's sinker was actually straighter and sunk more than in previous years. However, that can be explained.
Wang has always thrown sinkers that were miscategorized as two seamers, but there was a sharp increase in 2009:
So the movement on his sinker looked better in pitch f/x because all of the ones that were so flat that they were identified as two-seamers were taken out of the sample. So it's not that Wang's pitches sank less, instead they started running more side to side. So much so that they basically became a different pitch.
As Pat Androila pointed out at the the Hardball Times yesterday, Wang's numbers against lefties have always been bad, but were especially terrible in 2009. Why? I have a bit of a theory about this. I think Wang's increased side to side movement in '09 caused him to have difficulty throwing strikes (highest BB/9 of his career at 4.1), in addition to making the pitches that did travel through the zone much more hittable, particularly to lefties (gave up a 1.146 OPS against southpaws).
In general baseball terms, some pitches travel through the strikezone on planes that are more difficult to square up with than others. My contention is that those elite pitches find slots - angles of movement - that run counter to the barrel of the bat and minimize the time that they can be struck squarely. From the batter's perspective, this is similar to a golf swing. The longer your clubface is square through the impact zone, the better chance you have of hitting the ball straight. If your club is turning on the way through, you need to get very lucky to hit it flush.
Randy Johnson's slider was death to lefties because it crossed the zone from an extremely wide angle, diving down and to the right. Mariano Rivera's cutter is even tougher than lefties than it is on righties because it veers in on their hands and away from the thick part of the bat.
Though it seems odd to say now, Wang's sinker was one of those elite pitches over the course of almost three full seasons. Batters knew it was coming 3/4 of the time and still had trouble making solid contact. I remember Brandon Inge saying during an interview played on a broadcast that he used to literally try to swing under the pitch and would still sometimes drive it into the ground.
Take a look at these two graphics I made from Wang's at bat against Nick Markakis in the first inning of the game on April 8th, 2009. But keep in mind that this is far from exact; I'm trying to provide a 2-D visualization for a 3-D problem. The yellow lines represent some potential slots that Markakis' bat could fall into while the red represents the trajectory of Wang's pitch. The graphic on the left is meant to resemble a sinker and the one on the right shows what pitch f/x would classify as a two-seamer.
An effective sinker by Wang is running nearly perpendicular to the bat once it reaches the strikezone, while his drifting 2-seamer is much closer to parallel. They often say baseball is a game of inches and the break on Chien-Ming Wang's sinker is a perfect example of that.
Of course, this doesn't get to the part of the scenario that any team looking to sign Wang actually cares about: Will he ever be able to command the sinker that made him so effective before his injury in Houston again?
When Wang is finally able to pitch this year, it will have been almost two years since he could throw enough effective sinkers to be a solid Major League starter. It seems as though the Yankees messed up his rehabilitation by telling him not to exercise his legs when recovering from his lisfranc sprain, which probably contributed to his inability to find his old sinker. It took an intricate combination of forces and no small amount of touch to toss that pitch and his failed rehab might have thrown him irreparably off course. To continue with the nautical analogy, he might have already run ashore and there's no telling if he will be able to rebuild his ship.
The troubling part is that the line between being awesome and awful for Wang is so thin. It only takes one bad pitch to ruin an at bat, and just a 17% drop in good sinkers made him one of the worst pitchers in the history of the game over his first three starts. He's never thrown good enough offspeed pitches to get guys out so any team who gives him a deal is betting on whether or not he recoups the magic sinker. Personally, I hope Wang finds it. Objectively, I don't think he will.