Steve Blass Diesase

In a 10-year career, Blass posted a 103-76 record with 896 strikeouts and a 3.63 ERA in 1597 innings pitched.

Blass is best known for his sudden and inexplicable loss of control after the 1972 season. His ERA climbed to 9.81 in the 1973 season. He walked 84 batters in 88 innings, and struck out only 27. Blass suffered through the 1973 season, then spent most of 1974 in the minor leagues. He gave it one last try in spring training of 1975. Failing to regain his form, he retired from baseball in March 1975.

Thereafter, a condition referred to as "Steve Blass Disease" became a part of baseball lexicon because such a change in a player's skill was identified with him. The diagnosis is applied to talented players who inexplicably and permanently seem to lose their ability to accurately throw a baseball. In Blass's case, the sudden death of teammate and friend Roberto Clemente in a plane crash has often been considered a catalyst for Blass's sudden decline in 1973, as a way of survivor guilt even though Blass was not on the plane with Clemente.

- from Wikipedia

Players who have been said to be afflicted with Steve Blass Disease are: P Rick Ankiel (now an OF), P Oliver Perez and 2B Chuck Knoblauch. A possible case is the Detroit Tigers pitcher, Dontrell (D-Train) Willis, who is currently coming back after being diagnosed with "anxiety disorder".