When the Knicks sprinkled their roster with veterans who brought in championship résumés, the one thing they weren’t expecting was panic. They’d seen it all, been through it all, and came away with rings.

But now, with what the team readily admits is a must-win game tonight at Bankers Life Fieldhouse, the Knicks find themselves splintering into an odd assortment of injuries, illness and squabbles. When they most need to be united, they’ve found themselves wondering what’s left to fight for.

A still ill J.R. Smith was curiously absent from practice again, and according to coach Mike Woodson, a question mark for tonight. He’s been out of sight and suddenly silent on his very active Twitter account since rumors surfaced of nightlife interfering with preparation. A sick Kenyon Martin also was missing for the second straight day.

Adding to the troubles was Iman Shumpert sitting out with a sore left knee, the same one he spent the last year recovering from a torn ACL.

But the illnesses likely will fade in time for tip-off, and Shumpert insisted he’ll be on the court. The other problems might be a bit harder to resolve.

The Indiana Pacers’ stifling defense and physical play has led to frustration, but it’s been, as Tyson Chandler said Sunday, “self-inflicted.” While this may be Carmelo Anthony’s team, Chandler was brought in with a championship pedigree and a determination to do whatever it takes to win. All of this makes the odd confluence of words seem unlikely and untimely.

Chandler referred to the Knicks’ troubles and bemoaned a failure to execute the game plan on defense and the selfishness on offense.