In an upper-deck seat behind home plate, he sits alone with a large scorecard, a creased sports section, and a collection of stat books. Holding a pen in his mouth, he confidently flips through the paper, scanning the standings and league leaders.

When Sammy Sosa steps up to face Colorado Rockies pitcher Denny Neagle, the man grabs one of his books to see how the slugger has fared against the veteran southpaw. He carefully jots down a note next to Sosa’s name.

There’s something surly about this guy. He must be in his late 60s, and he doesn’t seem particularly happy. He appears lost in a world of facts and figures, yet he’s full of passionate opinions. Without warning he’ll serve up a quick and ferocious bark, like a sleeping dog unexpectedly awakened. He glances up from his scorecard, a vein bulging in his neck, and shouts at the umpire by name: “That pitch was a foot over his head, Hernandez. Go back to school.”

His presence is reassuring. Younger fans–the majority of the crowd–seem more interested in slamming beers and talking on cell phones than in following the minutiae of a ballgame.

As Gary Matthews Jr. misses a bunt, I take a shot at manager Don Baylor’s small-ball strategy. “Let him swing away,” I scream.

The man turns quickly to face me. Resting his thick glasses on the bridge of his nose, he sizes me up, and goes in for the kill. “He wasn’t trying to sacrifice,” the man spits contemptuously. “He was bunting for a hit.”

I tell him that Baylor favors sacrifices, even in lousy situations. The man seems surprised and possibly pleased that someone is willing to take him on. Not that he concedes.

“Did he look down for a sign, did he square away?” he questions me sharply. “Do you know the difference between someone bunting for a hit and bunting for a sacrifice? Do you? Do you?”

I answer “of course,” but I’m no longer certain. His ardor has thrown me off balance. As he returns to his scorecard, I try to focus on the game. Suddenly I want to engage him; I want his respect.

Tapping his arm, I begin complaining about Baylor’s base-at-a-time schemes. He counters that they’ve made a lot of sense most of the season. I argue they’ve been overused. After a few minutes, he loses interest and goes back to his scorecard.

The night stays sticky and the game grows tighter when Rockies centerfielder Juan Pierre makes a diving catch in short center. I tell my companion that Pierre is an impressive center fielder.

The silver head rises again. “He has less than 20 strikeouts too,” the man says before returning to the scorecard. I rule the exchange a victory.

In the bottom of the ninth the Cubs stage an unlikely rally to take the game. A mob of blue uniforms gathers around home plate for a group hug. I look down to see the man sitting silently, filling in the final figures on his scorecard. He packs up his belongings and brushes hastily past me. I lose sight of him in the crowd.