Sports Psychologist - game shape is such a volatile factor. Sometimes, no matter the minutes, some of your most important players just can't hit their best form in the worst of times like the playoffs, etc... This is where this guy comes in handy - he'll make sure they have their heads straight and will help keep their form up at all times, even if the minutes are suboptimal.
Do you have the control experiment where you have exactly the same set up but without the sports psychologist? Perhaps your key player would have been even worse.