The Cardinals' flaws were apparent when they were playing the Astros, but they weren't fatal, which was a nice change of pace after all the kind-of-postseason implications presented in the Dodgers series.
It was kind of like a practice session; even when the Cardinals made mistakes, or couldn't take full advantage of the many opportunities the Astros offered, we only had to imagine what the implications might have been if they were playing someone else. So far as I can tell, here are the flaws that might have mattered, if the Cardinals were playing a better team:
Pete Kozma: After a 1-9 run against the Astros Kozma is now hitting .257 with a BAbip of .375. His ascendance to the top of the Cardinals' depth chart at shortstop is fascinating to me for reasons like that—he's a mistake-prone player, in the sense that turned Tony La Russa against Brendan Ryan, only he also doesn't have any particular advantage over Ryan Jackson. He makes errors more frequently, he strikes out more often, he's unlikely to play a better shortstop, etc.
I'd love for Kozma, after all the crap he's gotten here and elsewhere, to turn into a useful utility guy, but that seems distinctly unlikely to happen; the difference between Brendan Ryan's numbers over the last three years in the majors and Kozma's numbers over the last two years in AAA is about 20 points of slugging percentage. Minor league numbers have failed to accurately represent a player's eventual Major League abilities before, but there's an enormous gap between what Kozma's done in the PCL and what would be acceptable in 150 at-bats in the majors when you're not 20 runs above average on defense.
Bullpen Wear Patterns: I can't confirm that Mitchell Boggs is worn down, but he is fourth in the NL in relief appearances, and carrying an unsustainably large gap between his ERA and his xFIP, so if Mike Matheny continues to go to him in every last close game he's likely to look like he's worn down while his ERA creeps back up where his peripherals suggest it should be.
MUBOGMOT, the Cardinals' not-especially-secret bullpen weapon, has made 30 combined appearances in 18 September games; at the same time Fernando Salas, who's probably no less effective than Boggs, has appeared in seven, serving three times as a mop-up guy and appearing in high-leverage situations when everybody else is gone or Matheny feels the need to go multiple innings.
I admire Matheny's desire to use his best relievers as often as he can—it's a welcome change from his earlier desire to use Victor Marte as often as he could—but a little more variety might do him some good here.
Tentative Starting Rotation: The Cardinals' rotation seems worryingly unlikely, as a unit, to scream obscenities at an opposing pitcher. I'm not sure how John Mozeliak plans on rectifying this, but I hope he starts this afternoon.
You'll have to excuse my brevity here—I'm in the middle of hanging stockings on the new Viva El Birdos with care, etc. Expect a post about some of the changes over the weekend, and the changes themselves sometime soon after.