"The Australian dressing room is fine. I don't know how many times we need to answer this. We're all pretty excited to be in an Ashes campaign. (Coach) Darren's (Lehmann) done a wonderful job, like all our staff and players," said Haddin, whose second innings 71 nearly led Australia to a stunning first Test win at Trent Bridge.
Arthur has reportedly claimed that skipper Michael Clarke had described teammate Shane Watson as a "cancer" on the national cricket team.
According to reports in Australian media, legal documents tendered in the Melbourne court showed that Arthur had felt like "meat in the sandwich" in the divisive feud between Clarke and Watson.
Arthur was sacked just 16 days before the first Test against England at Trent Bridge, a match the tourists lost by 14 runs on Sunday to go 0-1 down in the five-match series, and was replaced by former Australia batsman Lehmann.
Haddin questioned the timing of the claims made by Arthur, who in his departing press conference had talked about taking responsibility for the team's performances.
"I fail to see how this course of action is consistent with his words and I am disappointed that this has been released two days before such an important Test match," Haddin was quoted as saying by the Australian media.