One of the major stories of 2012 was Ubaldo Jimenez's season-long disaster in the rotation. The obvious culprit seemed to be his mechanics, though until now there's been no details forthcoming from either the Indians or Jimenez.
Most disheartening for him was how easily his life had become unraveled. In the spring of 2011, as a member of the Rockies, Jimenez developed an infection on the thumb of his throwing hand. Jimenez grips a ball differently than most everyone. Regardless of what pitch he throws, Jimenez will always put his thumb on the ball's seam to help guide the ball. At times this creates a blister. Sometimes that blister pops. In 2011, the blister became infected.
Jimenez began compensating for his blister by unknowingly changing his mechanics. And that's all it took. His pitches lost speed. He could no longer control the strike zone. Batters feasted. A high-profile trade to the Indians midseason in 2011 only added more pressure.
There's a lot more details about what Jimenez was going through besides the pure mechanical issues. And a lot of biographical background that I hadn't seen before anywhere. It's a long read, but it's more than worth it.