There are a couple of reputable sources asking what the heck has happened to Wandy.
This hasn’t been a banner year for Rodriguez, though. Through his first 13 starts, the 31-year-old has been lit up for a 5.60 ERA. That’s the highest mark among qualified NL starters. Has Wandy lost his magic?...
...While Rodriguez isn’t pitching at the same level as he did over the ‘07 to ‘09 period, that ERA does overstate the extent of his struggles — his FIP is 4.41 and his xFIP is 4.49. Rodriguez has been plagued by a .353 BABIP, second-highest among qualified Senior Circuit starters and well above his .314 career figure. Also, his rate of stranding runners on base has dipped to 62.5 percent. The MLB average is in the 70-72 percent range, and Rodriguez’s career left on base rate is 69.4 percent.
There's a lot more, and there's an excellent post at The Crawfish Boxes wondering the same thing:
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 is (obviously) more to be found within the posts, which are definitely worth killing a half-hour over, but both bring valid points. Wandy has been unlucky, kind of crappy, and is coming off a career year. Maybe 2010 Wandy is Normal Wandy, and 2009 Wandy was the product of a lucky, out of the norm season.