Arizona Cardinals head coach Bruce Arians has opened up about his split with the Pittsburgh Steelers in 2012, telling HBO's "Real Sports" that he felt betrayed when he was let go as the team's offensive coordinator.

Arians ran Pittsburgh's offense from 2007 through the 2011 season, when his contract expired. In the HBO interview, Arians recounted a discussion he said he had with Steelers head coach Mike Tomlin that led to his abrupt departure that offseason.

"I got a call on Monday and [Tomlin] said, 'I can't get you the money.' I said, 'OK,'" Arians said. "He said, 'No, I can't get you a contract.'

"I said, 'Are you firing me?' He said, 'No.' 'Well ... it's just a matter of words, Mike. OK. If I don't have a contract, I'm fired.'"

Bruce Arians said he was "legitimately retired" after the Steelers decided not to sign him to a new contract as offensive coordinator following the 2011 season. AP Photo/Rick Scuteri

The Steelers made two Super Bowl appearances with Arians as offensive coordinator, winning the title in 2008. Explaining why he felt betrayed, Arians said it was because he felt he had "done a good job."

"Maybe not the right image, but it was a damn good job," he said. "I was pissed. But again, time heals things."

Asked what he felt cost him his job with the Steelers, Arians cited his "style of offense," saying the team felt he "didn't run the ball enough." He also cited his relationship with quarterback Ben Roethlisberger, which Arians said the team thought was too close.

Arians said he was "legitimately retired" after he left Pittsburgh, but he went on to become offensive coordinator under Indianapolis Colts head coach Chuck Pagano in 2012, before taking over as interim head coach when Pagano was diagnosed with leukemia.

Arians has been head coach of the Cardinals since 2013.