We have mentioned something here called "Third Order Record" before. The glossary is here, but to keep things short, it's an estimate of a team's true performance from Baseball Prospectus that includes strength of schedule.
In any case, if you click here, (on 9/12, could change if you are reading this in the morning because you didn't stay up late), you will notice something interesting about the American League.
Namely, the Rangers' actual performance is estimated by BP to be worth just shy of 91 wins to this point in the season. That's a .618 winning percentage, and that's the best in the American League. Some time ago they estimated the Rangers were close to the best team in the League, but now they estimate that they are the best team in the league.
Means nothing in the standings, and does not guarantee postseason success, but it should make you a little excited about this team's abilities going forward. Especially considering that record would be even better if Mike Adams, Koji Uehara, Nelson Cruz, and Josh Hamilton were around for every game -- something they likely will be in October.
UPDATE: This is still true on the 13th, as well. Though, by a narrower margin.