If you're at all familiar with modern major league baseball, you know that the role of "pitcher" has been endlessly divided and subdivided - an ace starter who might throw a complete game, a "long reliever" who only comes in during garbage time, a closer who tosses only 20 pitches in the final inning.
The most unique of them all might be the knuckleballer, a pitcher who relies primarily on the knuckleball. Unlike every other pitch, the knuckleball is thrown with the fingertips and little to no spin, leading to an erratic flight pattern that can be maddeningly difficult to hit regardless of how slow the ball comes in. The chaos has a price, though; pitchers who use the knuckleball are always walking a tightrope - something as simple as a split nail or a stiff breeze can make it impossible for them to strike out batters.
Somewhat poetically, the careers of knuckleballers are as unpredictable as the pitches they throw, as the feature-length documentary "Knuckleball!" shows by following the ups and downs of Tim Wakefield and R.A. Dickey (the only active MLB knuckleballer):
Ricki Stern and Anne Sundberg directed the well-regarded Darfur war documentary "The Devil Came on Horseback," and they bring huge amounts of craft to what could have been a dry set of baseball stories. If you have any interest in baseball or sports at all, you'll probably like "Knuckleball!"