So it was that Baarns found himself in Oakland on Friday — and not just for any game. This was a contest with playoff stakes for two long-moribund teams having surprisingly successful seasons. “When they called me in June, the A’s were about 10 games out and the season seemed lost,” Baarns said as he walked the grounds before his broadcast began. “Now they’re close to winning their division, and I get to call a game in the middle of a pennant race. Who would have thought?”

Baarns — 34, bald, with a youthful face and a resonant voice — was so concerned about doing a good job that in preparation he had studied the stadium’s wind patterns and sight lines, worried that he might misjudge a line drive and give listeners the wrong sense of an unfolding play. He started studying both teams weeks ahead of the game, listening to podcasts, reading about their surges and disappointments (the Mariners faltered after the All-Star break but still cling to contention; the A’s remain one of baseball’s hottest teams).

Baarns called Korach, a longtime mentor, and got an insider’s scoop on the A’s. He received emails from Cotroneo, Korach’s radio partner. Both had similar advice: Have fun and be loose, they said. Just do what you’ve always done. Most of all, trust your stuff.