NEW YORK — Rain gave the St. Louis Cardinals a reason to consider changing their pitching rotation, which means the New York Mets might have to face Chris Carpenter sooner than expected.

Game 1 of the NL championship series was postponed Wednesday night because of steady showers, offering the Cardinals a chance to pitch their ace on full rest in Game 2.

The best-of-seven series will begin Thursday night now, and the second game at Shea Stadium is to be played Friday — which was supposed to be an off day in the series.

Carpenter had been slated to start Game 3 on Saturday, when the series shifts to St. Louis. But if the Cardinals decide to bump him up to Friday, he would be working on his regular four days of rest.