This probably needs a little work, so bear with me:
Win expectancy was dropping for the Mudville Nine that day;
Run differential stood at two with an inning left to play,
And then when Cooney died at first, and Barrows did the same,
Our OBP is sickening, cried the patrons of the game.
A straggling few got up to go like LA Dodgers fans. The rest
Clung to the intangibles within the human breast;
They thought, if only Casey could get a whack at that --
The Fangraphs chart would even up, with Casey at the bat.
But Flynn preceded Casey, as did also Jimmy Blake,
And the former was a hacker and the latter couldn't rake;
So upon the stricken multitude a melancholy fate:
Lineup construction left little chance of Casey at the plate.
But Flynn let drive a single, as wonderful as a walk;
And Blake went deep, but stood awhile to strike a pose and gawk;
And when BABIP was counted, and they saw what had occurred,
There was Jimmy with the XBH and Flynn flopping into third.
From 27,000 throats in this titanic struggle,
A "Woo" soared up and cross the river like a toxic bubble,
Picked up on Fox Sports Ohio and MLB's new app,
For Casey, high-OPS Casey, was advancing to the bat.
54,000 eyes were on him as he tugged his batting glove;
27,000 tongues applauded when he gave another shove;
Then when the crafty LOOGY brought the ball down to his hip;
Defiance gleamed in Casey's eye, his 'stache curled Casey's lip.
And now the four-seamed spheroid came hurtling through the air;
And Casey stood a-watching as if it wasn't there;
Close by the sturdy batsman, and nearly at his head;
"That sounded high," said Casey. "Strike one," the Fox Trax said.
From the Diamond Seats and bleachers, the fans stood one by one;
And tried to do the Wave, as if they lacked for fun;
"Kill it! Kill the Fox Trax!" shouted someone in the stands.
And it's likely that they would've, had not Casey raised his hands.
Bespecked by sunflower seeds great Casey's visage shone;
He tugged his batting glove some more, as if his hands had grown;
The pitcher got the signal, and now a cutter flew;
But Casey still ignored it, and the Fox Trax said, "Strike two."
"Fraud!" cried the maddened thousands, and Marty echoed "Fraud!"
One scornful look from Casey, and the crowd (except Marty) had been awed.
They saw his face grow stern and cold, unenhanced muscles strain,
And they knew that Casey wouldn't let (seriously, don't you hate it when poets try to rhyme "again"?)
The 'stache curls up from Casey's lip, his teeth are clenched in hate;
He pounds like John Roseboro his bat upon the plate.
The belly-itcher holds the ball, and now he lets it go,
And the humid air is shattered by the force of Casey's blow.
Oh, somewhere in a market small, Pythag is shining bright;
Beach Boys are playing somewhere, and the pennant is in sight,
And somewhere men are blogging, and Little Leaguers work the count;
"But strikeouts only hurt your feelings," mighty Casey tweeted out.