Strongest and Weakest Divisions in MLB

Yesterday I wrote a post about how strong the AL East is and how hard it is for a small market team like the Orioles to compete in it (although I note that the small market Rays have managed to compete quite nicely, thank you, at least for the last three seasons).  An obvious follow-up would be to look at how MLB’s other divisions have done when playing against outside teams.

The conventional wisdom is that the AL East is the strongest division in baseball by far.  Do the actual numbers back up the conventional wisdom?

Yes, they do, at least so far in 2010.  As mentioned in yesterday’s post, AL East teams have a .555 winning percentage when playing outside their division.

No other division comes close.  The next strongest division this season is the NL West, with a .525 winning percentage against outsiders.

Only a few seasons ago, the NL West had a reputation as one of MLB’s weakest divisions.  Things can change quickly if several bad teams in a division can turn it around.  The Giants and Padres have rather suddenly become strong teams in the last two seasons.

The NL East is a close third with a .519 winning percentage against non-division opponents.

What is more interesting about the NL East, however, is how evenly matched the teams are when playing within their own division.  The Braves and Phillies have the best in-division records at 21-20 and the Mets have the worst at 21-24. 

That’s parity, at least when playing within the NL East.

The weakest division in MLB this year by far is the NL Central.  It has a .434 winning percentage when playing against teams in other divisions.

The only NL Central team with an winning record outside the division is the Cardinals with a 35-29 record.  The Reds, who have made such an exciting turn-around this year, are only 30-30 when playing teams outside of the NL Central.

Here are the records and winning percentages of each division in baseball as of today (note that I have not updated the AL East’s record since yesterday) when playing non-division opponents.

AL East  188-151, .555 winning percentage

NL West  187-169, .525

NL East  182-169, .519

AL West  149-156, .489

AL Central  171-186, .479

NL Central 155-202, .434

With America’s largest metropolitan areas disproportionately located on the East or West Coasts, it should, perhaps, not be surprising that the AL Central and NL Central, comprised of mostly Mid-West teams, should be the weakest in baseball.

With the exception of the two Chicago teams and Houston, the markets in the center of the country just aren’t that big, and aren’t growing nearly as fast as metropolitan areas on the coasts or in the South and Southwest.