Yep. But they also talk about how the game died off - the Kings won the world series and hardly anyone came, during the waning days of Major League Baseball. If I remember right, he said no one had any time for the game anymore.
Of course, the Siskos are still big fans. And on the Federation colony world of Cestus III, the game is still played.
Michael Piller is a huge baseball fan, he's the one responsible for the baseball references in both this episode (which he wrote) and in DS9 (which he co-created).
Personally, I always thought baseball was a little slow for my tastes. So I always thought it was interesting how they talk about how baseball was too slow for people's changing, faster-paced tastes. (Shorter attention spans?) DS9 always makes me nostalgic for the sport, and I don't even like it!