Knicks GM Glen Grunwald’s work is done. But are the Knicks done, too?

Grunwald said he has built a team with a chance to break the club’s 40-year championship drought despite evidence to the contrary amid its recent doldrums. Grunwald did his final minor tinkering Thursday to the league’s oldest roster, adding another ancient piece and another former Nugget in signing as big-man insurance 35-year-old Kenyon Martin.

The long-anticipated addition was carried out in case center Marcus Camby (strained plantar fascia) and Rasheed Wallace (stress reaction) can’t stay healthy for the playoffs.

At Thursday’s trade deadline, Grunwald opened up a roster spot for Martin’s addition by shipping out-of-the-rotation guard Ronnie Brewer to Oklahoma City for a 2014 second-round pick. Martin will sign a 10-day contract but is not expected to play either Friday night in Toronto or Sunday against Philadelphia as final details get worked out.

It wasn’t much of an upgrade for a club that has lost four of its last five games, was humiliated in Indiana on Wednesday night and has been a .500 team since mid-December after beginning the season 18-5. Martin, with the Clippers last season, hasn’t played this season.

“That’s our goal. That’s what this organization is trying to do — move toward an NBA championship,” Grunwald said on a conference call, the first time he has talked to the media since Oct. 1. “Hopefully, we’ve made great progress on our goal. I think we have the parts to do so.’’

The Knicks still are second in the East — five games behind Miami — but have looked like a disjointed group recently, softer on defense, with no reliable secondary scorer to bail them out on Carmelo Anthony’s off nights. Grunwald admitted teams have adjusted to the Knicks’ offensive system.

“But we’re optimistic,’’ Grunwald said. “We obviously have to play better. We’ve had some difficult games. Teams go through that. I’m optimistic Woody [coach Mike Woodson] and the players will find a way to get back to their winning ways, get back to playing winning basketball.’’

Knicks brass wanted to do more, but didn’t have the favorable contracts or future pawns to make a splash. Grunwald said they were never close to trading young stud Iman Shumpert, who has been lousy since his return from ACL surgery in mid-January.