There are a lot of good stories in baseball this year. Some bad ones, too. But lots of good, like Rick Ankiel’s comeback and Tom Glavine’s 300th win.

I think the story of the 2007 Diamondbacks is interesting, to say the least. And it would certainly be a good story if they manage to hang on and win the division.

Chris Jaffe of The Hardball Times had this to say in a story called “No Mirage in Arizona” on Monday:

Many thought (the D-Backs) could be this year’s breakout squad. Here at THT, for instance they were the staff’s consensus to take the division. They had a fantastic ace in Brandon Webb, had retained former Mr. Everything Randy Johnson, and had an organization littered with promising young talent.

But even those optimists have been surprised. Sure, they’re winning, but they ain’t going about it in a particularly healthy way. At the moment I write this, they have scored 18 fewer runs than they’ve allowed, 537-553. Hmmm…

OK, let’s go back to Sabermetrics 101. There’s supposed to be some sort of relationship between runs scored and runs allowed. You can use some variation on the old Pythagoras formula to figure out how many wins a team “should” have based on its record. And you know, teams that can’t score as many runs as they give up really shouldn’t be on pace to win 90 games. Differences between Real W/L and Pythag W/L are dismissed as mere chance. Heck, in B-ref’s expanded schedules, the site flatly categorizes any variation as luck.

Yet the D-backs this year have done quite the job mocking sabermetric orthodoxy. Not only have they floated over their ordained record, but they’ve teased people into thinking they’ll regress. After bursting out to a 46-35 start (while getting outscored all the while), they fell apart and dropped 13 of their next 17. “A-ha! Mathematical certainly [sic] will not be mocked or [sic] long!” Well, accept [sic] in this case that is. Since then the D-backs have won 21 of 26. Sure they’ve outscored their opponents in that stretch, but only 140-116. They’re still wildly exceeding expectations.

Jaffe goes on to explain that a team can defy Pythagoras by performing extremely well in one-run games. But that isn’t the case with Arizona; it’s just not significant enough.

The trick is discovering that Arizona’s bullpen is, in Jaffe’s words, “bipolar.” Their big five relievers (Joe Valverde, Tony Pena, Brandon Lyon, Juan Cruz and Doug Slaten) have a collective ERA of 2.76.

The rest of the bullpen has an ERA of a horrific 7.09.

This causes the team to lose games by ungodly deficits and win tons of close ones.

Before I continue, let me just say that Jaffe’s article is a must-read.

I also liked the Diamondbacks before the season, but I picked the Padres to come out of the division. The Diamondbacks are in the bottom five of most offensive categories, and the Padres are as bad, if not worse.

What’s interesting to me, though, is that the Padres have a better rotation and a bullpen that’s as good as anyone’s.

The Padres are three games under their expected W-L as it stands, and they don’t seem like they’re going to make up that ground anytime soon.

I’m rooting for the Diamondbacks now anyway.

Just, out.