As of the Supreme Court's landmark "People v. Not Thinking About Pink Elephants" ruling, your elbow's only not a concern when the official website isn't running headlines like "Chris Carpenter's Elbow Not A Concern" ahead of Game 1 of the World Series. I don't think this kind of thing leaks just because somebody within the organization has decided it would be hilarious to make their own life more difficult, and the Cardinals probably are worried about Carpenter's elbow, seeing as it's got 254 innings on it this year.
That said, this strikes me as different, at least, from the dead-armed Shaun Marcum situation, of which the Cardinals just finished taking considerable advantage. Two of Carpenter's last four outings are complete game shutouts, and three of his last eight; one of his poor postseason outings involved pitching on three days' rest, and the other gave us less to worry about than any of the other Cardinals starts from the NLCS.
Marcum, meanwhile, ends the season having struggled in six of his last seven starts—the complicating factor being that he was excellent in August, so that that pulls back to seven of his last fourteen. When these things go, I guess, they go too quickly to allow for little things like hiding your own arbitrary endpoints.
Nevertheless, if—as Joe Strauss tweets—this was a serious concern starting after Game 3 and continuing as recently as the NLCS's would-be Game 7, and it's less of a concern now than it was then, I'm not ready to panic. Carpenter's stuff looked Carpenterian in Game 3, and thanks to that Game 7 not happening he'll be pitching with extra rest.
If he's not ready to go, I can only hope that the Cardinals find some way to win a game in the postseason while relying heavily on an extremely quick hook and a rested bullpen.
In any case, it would be only fitting if the Cardinals' ace failed to start Game 1—it's happened in each of their last three World Series appearances. In 2006 Carpenter and Suppan both were otherwise occupied, leaving Anthony Reyes to pitch the second-best game of his life—8 innings, two runs, four strikeouts; in 2004 Carpenter was injured and the rest of the staff was basically indistinguishable, leaving Woody Williams to get batted around Game 1 in Boston after Jeff Suppan outdueled Roger Clemens in Game 7.
It went on before that, too—in Game 1 of 1987 22-year-old Joe Magrane got blown out of the Metrodome, leaving John Tudor to start the Game 3 opener. The last time a Cardinals ace started Game 1 of the World Series—that is, the last time the Cardinals won an NLCS in six games—was 1985, when Tudor shut down the Kansas City Royals in Games 1 and 4 before falling apart with everybody else in Game 7.
Chris Carpenter is a great starter—better than Jaime Garcia, better than Kyle Lohse and Edwin Jackson—but baseball teams can win and lose the World Series with incredibly effective aces and intermittently effective rookie starters. If this team can avoid compounding disasters as brilliantly as it has so far, they'll be able to win with an effective Chris Carpenter or a—well, or a moderately effective Chris Carpenter.