But if you look at the data, it is almost impossible to draw that conclusion...
An AL East team plays their division rivals 72 times a year, and plays AL Central teams 35 times a year (roughly, since there is the occasional game missed by rainout or whatever). If the Jays switched over to the Central, they would be switching about 37 games from being against East teams to being against Central teams. Then the theoretical upper-bound of extra wins a move would give them is 37 - a situation which would arise if they always lost to East teams and always beat Central teams. Even in an absolute best case scenario such a move would not turn the 2004 Jays into the 2001 Mariners. A more realistic swing would be the situation where a team was a .450 club against the East and a .550 club against the Central. Moving that team from the East to the Central would give them about 3-4 extra wins a year. That is not a huge amount, but it could easily be enough to turn a very good team into a division winner.
I decided to take a look at Toronto's record against the Central and the East for each of the 6 years under J.P. Ricciardi. The Jays in 2004 were a .387 team against the East and a .406 team against the Central. That 19 point difference, spread over 37 games, would give the Jays an extra 0.84 wins. Round up, and we give the Jays one extra win in 2004 by moving them to the Central.
This a very rough, back-of-the-envelope method with sample-size issues abound - but it gives us a rough idea of the magnitudes involved in a league switch. I suspect a more sophisticated method would provide very similar results.
Here are the win adjustments for the Jays in the 2002-2007 period:
2002: -2 extra wins (78 wins to 76)
2003: 5 extra wins (86 wins to 91)
2004: 1 extra win (67 wins to 68)
2005: -3 extra wins (80 wins to 77)
2006: -3 extra wins (87 wins to 84)
2007: 0 extra wins (83 wins to 83)
If we drop those totals into the standings for the AL Central (and create an NL-Central like 6-team division), without adjusting the win totals for the other teams, here are the year-by-year standings:
2002
------
MIN | 94 | 67 | .584 | |
CHW | 81 | 81 | .500 | 13.5 |
TOR | 76 | 86 | .469 | 18.5 |
CLE | 74 | 88 | .457 | 20.5 |
KCR | 62 | 100 | .383 | 32.5 |
DET | 55 | 106 | .342 | 39 |
2003
------
TOR | 91 | 71 | .562 | |
MIN | 90 | 72 | .556 | 1 |
CHW | 86 | 76 | .531 | 5 |
KCR | 83 | 79 | .512 | 8 |
CLE | 68 | 94 | .420 | 23 |
DET | 43 | 119 | .265 | 48 |
2004
-------
MIN | 92 | 70 | .568 | |
CHW | 83 | 79 | .512 | 9 |
CLE | 80 | 82 | .494 | 12 |
TOR | 68 | 94 | .420 | 24 |
DET | 72 | 90 | .444 | 20 |
KCR | 58 | 104 | .358 | 34 |
2005
-------
CHW | 99 | 63 | .611 | |
CLE | 93 | 69 | .574 | 6 |
MIN | 83 | 79 | .512 | 16 |
TOR | 77 | 85 | .475 | 22 |
DET | 71 | 91 | .438 | 28 |
KCR | 56 | 106 | .346 | 43 |
2006
-------
MIN | 96 | 66 | .593 | |
DET | 95 | 67 | .586 | 1 |
CHW | 90 | 72 | .556 | 6 |
TOR | 84 | 78 | .519 | 12 |
CLE | 78 | 84 | .481 | 18 |
KCR | 62 | 100 | .383 | 34 |
2007
-------
CLE | 96 | 66 | 0.593 | |
DET | 88 | 74 | 0.543 | 8 |
TOR | 83 | 79 |
0.512 | 13 |
MIN | 79 | 83 | 0.488 | 17 |
CHW | 72 | 90 | 0.444 | 24 |
KCR | 69 | 93 | 0.426 | 27 |
Other than 2003, which:
- Was arguably the weakest 5-team division in the history of the American League.
- Had arguably the worst team in post-war American League history.
Can we please let this "if only the Jays were in the AL Central" meme die already? There is no credible evidence that, outside of 2003, it would have made any difference.