Does Matt Carpenter have another slump in his future?

We’ve reached the part of the St. Louis Cardinals’ intermittently just-barely almost-frustrating season where it’s worth asking how much air is left in Matt Carpenter’s offensive output. Not because the Cardinals lost, and we need reasons to not talk about bunting.

Not even because he was just in an awful slump, or at least not entirely because of that.

Because he was just in an awful slump and we already took for granted that it was a slump, or at least partially a slump, and not a vengeful small-sample-size reckoning. We’ve made our subconscious adjustments to his true-talent level; now it’s time to show our irrational work.

First, the slump. After going 1-4 with a double on July 26, in Atlanta, Carpenter’s OPS sat at .898, just short of the .300/.400/.500 plateau that was briefly a perfect way to explain his value. (He had to settle for .321/.396/.494.)

Over the next eight games, by way of a 1-31 skid, he went from a single off his season highs to .303/.377/.464—the difference, on the all-time leaderboard, between Jim Edmonds and Ray Lankford. A perfect Carpenter Game on Sunday—2-5, one double, one walk—and a 2-4 day Monday mean he’s back up to .306/.379/.468, which more than anything else says just how much easier it is to go down than up.

ZiPS, which is as good a place as any to begin asking this kind of question, is going to need some more at-bats. Its rest-of-season projection is .277/.361/.421, which would bring his 2013 total down to .298/.374/.455. That might seem pessimistic, but the full-season result is basically what he did in 2012, the last time he had a surprising breakout season.

It's also much, much higher than his original ZiPS projection: .257/.346/.388.

Everything Carpenter's done in the major leagues, after all, has been surprising. A guy who hits .300/.417/.463 in the Pacific Coast League (average line .286/.359/.448) is not supposed to find above-average power in the big leagues.

But he wasn't just a guy finding power in the big leagues: He was a 26-year-old with a track-record of solid hitting who found power when most players do. When you look at Carpenter's peers on Play Index—second basemen in the last 10 years with an OPS+ over 130—it's almost all guys who've reached their peaks and further developed their skill-sets. The major difference: Having come up as second basemen, the fans who watched them could safely restrict themselves to worrying about regression on one side of the ball at a time.

They'd also done their developing in the major leagues. Robinson Cano spent most of his first four seasons in the major leagues looking like a Pretty Good Hitter for an Infielder, the kind of player we might have hoped Matt Carpenter was; at 26 he found more power and started getting intentionally walked about as often as he was unintentionally walking before.

(If you're looking for a reason to be unduly optimistic about Carpenter's future, you could do much worse than Chase Utley, who dominates the list. Regarded as a platoon second baseman with an average glove until he turned 26, he blew past his career AAA line [.291/.370/.494] once he got a regular job.)

Maybe, then, our implicit reevaluation of Matt Carpenter isn't just outsized optimism. After all, ZiPS is having second thoughts, too.

Like Allen Craig, Matt Carpenter developed on schedule—these are supposed to be his peak years, after all—but outside St. Louis, allowing him to carry an outsized amount of his minor league value into the majors without paying the usual exchange rate. And like Allen Craig, the end result leaves him in a strange predicament: Already 27, he won't be able to stave off all the skepticism about his breakout until it's about to end.