RealGM

As just confirmed by Bud Selig, the sale of the Houston Astros to Jim Crane is official and the MLB is moving to a 15/15 team format in each league with the Astros now moving to the American League. Since next years schedule is done, the move will happen in 2013.

source: Jerry Crasnick twitter - https://twitter.com/#!/jcrasnick

http://www.vancouversun.com/sports/Houston+Astros+sale+contingent+move+American+League/5721659/story.html

http://espn.go.com/mlb/story/_/id/7242906/report-approval-houston-astros-sale-conditional-move-american-league

Will this expand interleague play through out the year?

Personally I wouldn't mind giving a team a series worth of days off, to limit interleague games.
---------------
Or maybe another NL(Rockies, Padres) team moves to the AL, and the AL splits the league into 2 division of 8.
East: Toronto, New York, Boston, Cleveland, Tamapa Bay, Baltimore, Detroit, Chicago,
West: Texas, Houston, Minnesota, Angels, Seattle, Oakland, Kansas City, Colorado/San Deigo
-------
Or Outside chance of 2 expansion teams no one has been talking about.

its about time they managed to fix the 6 team division and the 4 team division