Though production sources insisted the rehab veteran, 41, was terminated from the independent flick, titled Something About Her, because of creative differences, set insiders have questioned whether the REAL reason behind his shock exit was whether or not he showed up in a fit state to work.
"The director had no choice but to fire him on the spot," one source told Radar. "Everyone on the set was p*ssed and disappointed."
A cameraman working on the flick — filming in Big Sur and Santa Barbara, Calif. -- also told Radar that Arquette's behavior threw the whole film into crisis.
"All of the line producers were p*ssed off," Jorge Devotto revealed.
"David wasn't prepared that day and later on, I was told by colleagues that he was drunk. They tried to keep it all low-profile on set."
Said Devotto: "Anthony saved the day."
Back in June, he was spotted drinking scotch and hitting up strip clubs in Richmond, Va., while filming in town. Later, he was spotted drinking champagne and beers at The Abbey in West Hollywood, Calif.
When approached for comment, the film's director, Carl Colpaert, insisted Arquette left the project simply because, he claimed, the pair both he'd agreed with him that The Dark Knight star Hall was the better fit for the role he was slated to play.
"He absolutely never was drunk on set and I had no concerns about his preparedness for the role," Colpaert told Radar.
A pal close to Arquette reacted to the news in typical understated fashion that we have come to expect from the Hollywood fan favorite.
"David told me that he was doing this scene and as he's doing it, he was thinking, 'Anthony Michael Hall would be better playing this character than me,'" the source said.
"He finished up his day's work and drove home. He walked in the door and gets a call saying the director wants to talk to you. He said, 'I'm really concerned. You're not getting this character. We have such a tight schedule.'
"David joked to me, 'Essentially, I just got dumped by an actor who's better for the role!"
The Arquette friend added: "He was never drunk on set. No. He worked a full day, drove home. He never drives a car if he has a lick of alcohol."
"Honestly, he wasn't that upset about getting fired because it was a bit of a shoddy production. He didn't do anything on set to like upset anyone. If people are saying he was drunk, perhaps it is because there were a lot of lines and he had a little bit of trouble with them."
Quizzed about the sudden departure, Arquette's rep, Cindy Guagenti, told Radar he had left the film amicably.