Should Jim Crane's bid to buy the Houston Astros be approved, there's a solid chance that they'll move to the American League West, thus balancing the two leagues at 15 teams each, broken down into three 5 team divisions in each league. You may have already read about that elsewhere.
With an odd number of teams in each league, the schedule would require that an interleague series be going on every day. In that way, the lone interleague matchup would receive far greater attention than the current system that features dedicated periods of interleague play for everybody and one lone National League matchup.
How would the schedule play out? I've been pretty vocal about getting rid of the unbalanced schedule. Playing 18 games against each of your division opponents is just too many. The schedule I'm hearing that's being considered, however, doesn't eliminate that, but it does reduce the number from 18 to 16 games. So each team would play two three-game series and a one two-game set, home-and-home, for a total of 64 games.
Teams would then play eight games each against the other 10 teams in their league, broken down into home-and-home four-game series, for a total of 80 games, bringing the total to 144 overall.
The interleague games would total 18, with 15 coming against another division - three games each - and another three against your declared rival. In the Nationals' case, that would be the Orioles, and would mean that unless the NL East was playing the American League East that season in the rotation of divisions, there wouldn't be home-and-home series against Baltimore every year.
The grand total is still 162. I'm told it's been worked out on paper and seems to have few flaws. Could it be implemented by 2012? I guess so, but the approval of Crane, who apparently carries some annoying baggage from his corporate life, is taking longer than most people thought it would, so the decision could be delayed a year.
Personally, I'd prefer the Arizona Diamondbacks switch leagues, since the Astros have been in the NL for 50 years now, but moving Arizona - which also has pretty recent new ownership - would require switching Houston to the NL West. Perhaps Major League Baseball is only comfortable with one divisional switch.