Various sources are mentioning the possibility of realignment in the Major Leagues, including shipping Houston to the AL and having an odd number of teams in each league.
My plan: Keep the AL and NL as they were in the 1960s with 10 teams each, and put all of the 1969-97 expansion teams in the third league. During the 1981 strike, there was talk of a third major league; there was also talk before the first round of expansion in the 1960s. Playoff spots would go either to the top 3 spots in each league, with #9 playing #8 in a single game before the first round series began, or to the league champions with only one wild card.
This has the advantage of not needing or requiring interleague play in September when the pennant races are most intense. If there is no interleague play, teams would play their 9 opponents at home 9 times each and away 9 times each over 162 games. With interleague play, the schedule becomes more difficult with a 162-game schedule. The 162-game schedule was originally devised for a 10-team league; the leagues made it work for a 2x6 and 2x7 league, until the NL didn't like their 2x7 schedule.
Ignoring effects on scheduling, the 2010 regular season results and playoffs:
Playoff: CIN at ATL., may be played on the same day as the opening game of the postseason.
- #9 TOR (X) at #8 TEX (A), winner to play #1 PHI (N);
- #7 CIN/ATL (N) at #2 TB (X)
- #6 SD (X) at #3 NYY (A)
- #5 SF (N) at #4 MIN (A)
First-place finishers were seeded 1-2-3, second-place finishers 4-5-6, and third place finishers 7-8-9. The second-round series would feature at least one matchup with teams from the same league, making a World Series between two teams from the same league less likely.
The four-team playoff would require the wild card team to play against their league champion in the first series instead of the World Series, so 2010 would give MIN vs NYY and TB vs PHI.
The other problem posed is the differing rules relative to pitchers batting or DH. Most professional leagues in the world allow some form of a DH; exceptions include the National League and Japan's Central League. The DH was used in the World Baseball Classic. NL purists could be satisfied with this compromise: Allow teams to use a DH, but require the pitchers to bat as well. This will put 10 players in the batting order. No double switches could be made with the DH, but a triple switch could be made if the DH takes a position in the field with another position player switching at the same time. Example:
[1-9 as in the MLB rulebook, but no positions assigned; I am not intentionally inserting myself into this lineup]
In the next half inning, Irwin, Jones, and Abel are due up. Jones is replaced as pitcher by Miller. Since we don't want the relief pitcher to lead off, we want a double switch. Hooker is replaced at catcher by Edward, but the DH-C switch leaves a hole. The manager announces the new DH position will occupy the 10th place in the batting order, and as it turns out, Lopez bats in that place. Miller will bat in the 8th spot in the order.