Body and Soul, by BH Fairchild, is the best sports poem I can think of. And here's one I suspect you all know, but it belongs on the thread:
Pitcher
by Robert Francis
His art is eccentricity, his aim
How not to hit the mark he seems to aim at,
His passion how to avoid the obvious,
His technique how to vary the avoidance.
The others throw to be comprehended. He
Throws to be a moment misunderstood.
Yet not too much. Not errant, arrant, wild,
But every seeming aberration willed.
Not to, yet still, still to communicate
Making the batter understand too late.