Maybe that should be a reality show, but it isn't. I want to compare the Athletics and Angels according to Net Runs Above Average and then compare their pitchers using PRAA and PRAR. Let's see how they stack up against each other to get a better feel for who could be the better team down the stretch.
Oakland has the better offensive/defensive combination by the sum of 40.16 Net Runs Above Average. That is a great deal of runs and makes me think the A's are capable of winning the division handily, and taking it soon. But we have not checked out the pitching situation yet. Something has to be making Anaheim win, and if it is not offense and defense, maybe their pitching is superior. Let's take a look at that.
Angels starters are three Pitching Runs Above Average (PRAA) better than the Athletics starters, but that can be explained away by the absence of Rich Harden in the rotation for a time. He easily would have added 3 more PRAA to his total in the starts he missed. They are also 5 Pitching Runs Above Average (PRAR) behind, but that is a small total (one that again is bigger if Harden's injury is taken into account.) An argument could be made they do not have the depth Oakland does in the rotation, but they make up for that with their bullpen. The Angels pen is one PRAA ahead of Oaklands (again, we have injury to blame. K-Rod was out and Scot Shields was the only dominant force in the pen. Huston Street was out as well for the A's, so this issue is cloudier than the rotation one). Their PRAR is huge though; 22, and it would be even more if they ignore Kevin Gregg (which they have been doing as of late from what I hear).
This is how the Angels have been winning. Their offense and defense is no match for the A's, their rotation is of a lower quality, but their bullpen trumps the A's pen. With their smallball tendencies the pen is even more important than it is for some teams, because they are supposed to keep the Angels in games while they scrape and claw back into it. Not exactly the best strategy for the playoffs though; when the Angels have to face teams like the A's who are better at everything except using their bullpen. There could be issues if the A's beat up on an Angels starter and the game is lost early on (think ALDS against Boston in 04'). If the Angels offense is not running on full cylinders like it did in the 2002 playoffs then they will not succeed in a 5 or 7 game series with a more complete team like Oakland. If Joe Kennedy and Jay Witasick can continue pitching well out of Denver then the Angels bullpen advantage is slimmer than it appears now, further lowering their chances of winning the division.
If you notice, there is only one big NRAA gun on Anaheim, and that is Vlad Guerrero. If he slumps for a significant period of time (only a .208/.264/.376 line in July) the Angels will suffer for it. The A's on the other hand have Crosby, Johnson, and Chavez (.379/.440/.699 in June and .272/.333/.495 in July) to maintain the offense (and if emergency struck, possibly Daric Barton for a short time). Depth is the key to the A's stretch drive, and as much as the Angels can survive through injuries I don't think their depth matches up with Oaklands.
One last thing; Oakland is a better team than the numbers show here, because many of these players are playing better since the end of May or so than their season total suggests. Jason Kendall and Eric Chavez are worth much more than their NRAA suggests at this point, which I believe could increase the A's advantage of NRAA to as much as 50 runs above average or more. It will be an interesting race down the stretch for the AL West with these two teams.