Arrivederci Andrea.

Andrea Bargnani, who started all seven preseason games in an experimental jumbo frontcourt, is expected to be demoted to the bench for Wednesday’s season opener against the Bucks at the Garden.

Though coach Mike Woodson refused to make it official, all indications point to Bargnani becoming a reserve, Metta World Peace starting at small forward and Carmelo Anthony heading back to power forward.

Consider the big frontcourt experiment of Tyson Chandler-Bargnani-Melo a preseason failure.

Woodson still said he wants to “sleep on it’’ but Anthony said he believes it’s happening.

Bargnani, the key offseason acquisition, shot just 20 percent from 3-point range and struggled with defensive rotations and rebounding. Anthony also shot just 37.5 percent in preseason. The chemistry didn’t seem right after the preseason opener. Bargnani was a minus-72 in the last six exhibition games.

“I didn’t expect it, we didn’t expect it,’’ Anthony said. “That’s what he’s going with. I think guys are ready for the move. Everyone seems on board with that. Whatever position we have to play, we have to go out and do it.’’

Anthony thrived at power forward last season in his career year in which he finished third in the MVP voting. Woodson is going with what he knows worked, but if Bargnani had thrived, this wouldn’t have happened.

“It really doesn’t matter to me,’’ Anthony said of playing the 3 or 4. “I’ve been successful in this league at the three. Last year I was successful at the four. Whatever adjustments I have to make, I have to make. I’m willing to do that.’’

Woodson said he was leaning toward Anthony at the power forward. The Knicks coach added, though, he may rotate the starters pending the matchups this season. Woodson also said Iman Shumpert will start at shooting guard, leaving World Peace the only logical option to start at the 3.

“We’ve been successful with Melo playing a lot of four’’ Woodson said. “We haven’t experimented a whole lot with him playing three until this exhibition season. I just feel like I didn’t want to go away from it a lot with him playing the four spot, but I have options. When I do go away from it. I can go big with Andrea.’’

Anthony denied he had any influence on the decision.

“I don’t have input on that stuff,’’ he said. “When they tell me I’m going to the four, I bow my head and say I’m ready. It’s simple with me.”

World Peace gave the team better chemistry with his tenacious defense and even hit 40 percent from the 3-point line in the preseason.

The concern is how Bargnani will handle the demotion. Last weekend, Woodson admitted he was “beat up’’ Toronto.

Bargnani on Saturday admitted his pneumonia that knocked him out of the European Championships prevented him from being in game shape in October.

“Maybe the word beating up wasn’t the word I should’ve used,’’ Woodson said. “Players in organizations go through roller-coaster rides, especially when you’re a high draft pick and expectations are so high. I was glad we had the opportunity to pick him up this summer. We’re going to see what he’s made of here. I got to coach him up and get him playing on a high level.’’