I checked the Orioles site just now and sure enough, only single tickets in a number of sections are currently shown as available.
Must be a full-scale Phillies invasion planned...interesting that it would become nearly fully subscribed this soon, since at Preparation H Park at Camden Yards even the Red Sox visits don't sell out anymore (in the Woes' season-finale home series last year against Boston, all three fixtures drew less than 30k).
