“The Real Housewives of New York City” debuted a Season 9 teaser on Monday — but sources tell Page Six the number of episodes this season could be slashed because the new cast did not provide enough heat.

The trailer came with a season premiere date of April 5, and while the show wrapped filming over the weekend, we hear Bravo has yet to commit to how many episodes will run. Sources said that number could be as few as 14 — down from 20.

“They are talking about cutting down the number of episodes in the series this year,” said one source familiar with the show, which added Tinsley Mortimer to the cast after Season 8 newcomer Jules Wainstein flamed out.

“Nothing happens,” said our source of the new season that just wrapped. “Tinsley was a dud. The other women have been doing this for years and she had no real training.” (Well, besides her short-lived 2010 show “High Society.”)

Another source said Bravo will have “more than 14 episodes, but it’s too early to tell how many.”

Page Six previously reported Mortimer’s “storyline” would involve her search for love in New York. But she’s not featured much in the trailer, which focuses more on the engagement of ­Luann de Lesseps, as well as Sonja Morgan, Dorinda Medley and Ramona Singer tipsily fighting on a trip to Mexico, Bethenny Frankel jumping naked into a pool, and Carole Radziwill opining on the presidential election. Onetime fan favorite Jill Zarin — who taped just one episode for the season after five years away — is in the trailer, leading insiders to believe Bravo is testing the waters to see if she should be brought back.

Either way, we hear there’s not enough juicy footage to warrant the show’s usual number of episodes. It hasn’t had fewer than 20 episodes since Season 5, and last year was capped off by a three-part reunion special.

We further hear the number of episodes could hit some of the “Wives” in the pocketbook because some are paid per episode rather than a fee for the season, a source said.

Bravo had no comment.