When the normally optimistic Kristaps Porzingis sounds the alarm, that means trouble.

By the time coach Jeff Hornacek tabbed rookie guard Ron Baker to start the fourth quarter at Bankers Life Field House, it was way too late this time. The Knicks were down by 26 points and Hornacek already had his eye on getting back to snowy New York.

After being heroes in Milwaukee on Friday, the Knicks turned into zeros against the Pacers, suffering a letdown of massive proportions in a 123-109 loss. The defeat sent team president Phil Jackson’s club to its seventh defeat in eight games.

Once 14-10, the Knicks (17-20) have fallen hard — as they did last January — and they may not recover because they have become a defensive wreck.

Porzingis said he never felt the Knicks were jelling, even when they were 14-10, instead getting by on talent, and he sounded as uncertain as he has this season in terms of their future prospects.