Maybe, but the other aspect I was considering is how fans travel. Baltimore won't get fans traveling from Los Angeles, Kansas City, Milwaukee, Minneapolis or Oakland.
But they will from the likes of Philly, New York, Boston, Toronto, etc, especially as the O's continue to win and the weather gets nicer.
But if the O's can draw 25,000+ locally for an April weekend series against the A's, then I would expect some huge attendance numbers the rest of the season.