The Yips is no mythological plague. For reasons unknown, players can encounter a mental hurdle that flat-out won't permit them to complete one of the game's mundane on-field tasks. (http://m.mlb.com/news/article/47124896/the-yips-difficult-to-understand-difficult-to-cure)
"Performers are often reluctant to discuss stagefright. They think it's bad luck. (Likewise, most baseball players do not want to discuss the yips.)"
- Joan Acocella, "I Can't Go On!", 3 August 2015 The New Yorker (http://www.newyorker.com/magazine/2015/08/03/i-cant-go-on)