I disagree, he just revealed that he is a mental case and that hurts in baseball, because baseball is a more mental game than more linear sports like basketball and football. I could also argue that basketball players don't lose their ceiling as easily (barring injury) because the game is almost purely physical. Unless you're a PG then a slight increase in mental demand but nowhere near baseball. Same goes for football unless you're a QB.
All sports players are susceptible to losing ceiling if they display incompetence or fragility. Adell displayed incompetence, Brandon Wood also displayed incompetence.