The 23-year-old O'Connor, who left the Force in acrimony two years ago, was criticised for his performances at fly-half for the Wallabies during the British and Irish Lions series and then told by the Rebels to seek employment elsewhere from 2014.
O'Connor had joined the Rebels from the Force in 2011 after a bitter wrangle over a contract extension, with the talented back claiming the Force lacked the ambition he expected.
However, the Force now appear to be O'Connor's only hope for a deal to stay in Australia, with club management telling local media earlier this week they were considering offering him a contract, but only if he fit into the team culture.
Western Force flanker McCalman agreed with that assessment of O'Connor, who has come under fire for his off-field behaviour and a perceived lack of discipline.
"He's a great player to have on the field. He's very skilful, with natural talent," McCalman said.
"But in saying that, we've worked very hard over the last year to set values and standards through captain Matt Hodgson and the senior players.
"We'd love to have him here, but not at the cost of compromising what we've already set up. Hopefully he sorts those things out and he ends up here."
McCalman's comments about O'Connor's attitude echoed those made earlier this week by Rebels and Australian loose forward Scott Higginbotham, who praised O'Connor's playing ability but added that his departure was the right move for the club.
"It was more a selection issue and how the club felt he fitted into the team dynamic," Higginbotham said. "With a lot of young guys coming through and new guys shining, it was a time to start fresh.
"It was a good opportunity and I think it's just what had to happen."
O'Connor's dumping and a seeming lack of enthusiasm by the Australian franchises to hire him are a far cry from two years ago when all five were clamouring for his signature.
The Force broke off contract negotiations with O'Connor in 2011, reportedly infuriated at his demands that the club meet key performance indicators related to a number of factors, but particularly player recruitment.
O'Connor's tenure at the Rebels was blighted by injury, but also several off-field indiscretions, most recently while in the Wallabies camp when he and good friend Kurtley Beale were photographed at a fast food outlet at nearly 4am in the lead-up to the second Test against the Lions.
O'Connor's public response in the wake of the controversy, snapping at reporters who questioned his discipline, sparked further criticism and irked Wallabies management and senior players.
The pair also reportedly missed the bus to training during the build-up to the third Test in Sydney, which the Lions won 41-16 to clinch the series, and local media suggested the Rebels' decision to cut O'Connor loose was to improve their chances of keeping Beale.
Beale has had discipline issues of his own this season, being stood down twice by the Rebels for alcohol-related incidents and he spent time in a private health clinic.
Higginbotham, however, said apart from his off-field issues, Beale was a valued team-mate.
"He's a great team player and the rest of the playing group really do enjoy and love playing with him," said Higginbotham.
"If he sorts out those off-field issues, then there is no issue with him."