Cardinals' sin up the middle

One of the key components of the stretch drive is that you have to cut bait on the things that aren't working, and start finding, trading or adding things that do. It's more important when you're locked in a tight race with few guarantees that your team will come out on top. Add in the approaching trade deadline and the chances that your divisional rivals might do something to help themselves while you stand pat, and the motivation to fix what's broke becomes all the more pressing.

The reason I belabor all this obviousness is because it's where the Cardinals ought to find themselves with the pesky matter of their middle infield, and particularly their middle-infield defense. As Chuck Yeager might have put it, the Cards have pushed the envelope when it comes to their infield defense.

That was admirable, up to a point. In 2009, moving Skip Schumaker from the outfield to the keystone was a creative solution to the twin problems of limited resources and a weak offseason market for second basemen. Similarly, trading for Ryan Theriot last winter was a smart adaptation to a limited supply of available options at short. But now, with everything at stake and three serious rivals in the NL Central, the Cards can't afford to leave nagging problems unaddressed.

It's time to admit that Schumaker's conversion isn't going to be an honored addition to the franchise's legacy of moving Mike Shannon from the outfield to third base, let alone give them the next Davey Lopes. And it's also time to acknowledge that Theriot was moved to the right side of the bag for cause. Since becoming a second baseman in 2009, Schumaker's Fielding Runs (from Baseball-Reference.com) have moved from a historically awful -10 to -8 in 2010; switch over to BIS' Defensive Runs Saved, and he started out at -11 and dropped to -9. In his time limited by injury this year, Schumaker's only hurting the Cardinals at -2 ... and still is essentially costing the Cards a win over a full season with his play afield.

Theriot's defense has been far from an asset, costing the Cards -14 in Defensive Runs Saved, or -10 Fielding Runs. That's a win lost to bad fielding at shortstop in a half season.

Even though fielding data is still more suggestive than conclusive, does anyone think that the Cardinals really want to risk losing another win or two to middle infield defense down the stretch?

Theriot's problems at short were already generally accepted, and he's a good glove on the other side of the bag, so it isn't like the Cardinals are in trouble employing him at all. If they add a slick-fielding second baseman, maybe that compensates enough for Theriot's problems at short; on the other hand, if they add a good glove at short, Theriot would go from defensive problem to defensive asset on the other side of the bag.

It also isn't like Schumaker's difficulties are a surprise -- he's done a great job improving his work around the bag, and he's as good a second baseman as he's going to be. At the highest level, it's still not good, and there comes a time when you have to give up on favored projects and get serious about putting the best team possible on the field. Adding a better defender would help the rotation top to bottom, but perhaps ground-ball fiend Jake Westbrook in particular.

It's worth mentioning that this is also an area where GM John Mozeliak and company can help the lineup as well. That may seem like a relatively minor consideration when the Cards are tied with the Reds for the NL lead in runs scored per game, and when Clay Davenport's Equivalent Average stats judge the Birds as boasting baseball's best team-wide offense, rating with the Red Sox.

But that performance has been despite Schumaker, entirely negating the purported offensive benefit to switching an outfielder into the infield in the first place. Schumaker's .251 EqA is below-average for second base (.260 for all MLB second basemen), and it was last year (.249, to the MLB average of .263). Schumaker was above-average offensively in the first year of the experiment back in '09 (.272 to .262), but he's no longer a young player in his prime, he's a thirtysomething with a bad glove and negligible offensive value.

Some luggage you pay to carry, and some it pays to carry. Schumaker's not worth it either way. The good news is that because Ryan Theriot would be worth moving across the bag, they can shop around for both shortstops and second basemen, and find the best short-term rental.

For myself, I like the idea of the Cards taking on some risk -- Rafael Furcal might be a dodgy proposition given his fragility, but the upside could be a nice one-two punch atop the order of Furcal and Theriot, or a Theriot as the “second leadoff man” in the nine-hole should Tony La Russa want to get back to batting his pitchers eighth anything more than sporadically.

Christina Kahrl covers baseball for ESPN.com. You can follow her on Twitter.