Former Sydney Swans and Melbourne coach Paul Roos has thrown his support behind returning St Kilda coach Ross Lyon, saying that the man that most recently led St Kilda to a grand final was a proven entity.

Lyon was appointed coach at the Saints earlier this month after the sacking of Brett Ratten following a review of the football club run by President Andrew Bassett.

The 56-year-old had been linked with the vacant Carlton and Essendon jobs across the last 12 months but was reluctant to go through a competitive process for either position and thus was ruled out by the respective clubs.

Speaking on Zero Hanger TVRoos said he feels the Bombers and Blues may have missed a trick in not appointing Lyon.

"I think Carlton made a mistake in not hiring him, I think Essendon made a mistake in not hiring him," Roos said.

"I understand clubs have to go through processes, (but) he's an elite coach. Look at his coaching record, (if) the ball bounces one way instead of the other way he wins a premiership. I think he's an exceptional coach and will do an exceptional job."

Roos, who worked with Lyon during their time in Sydney, said that while the Blues may have made the right choice in hiring Voss, the interview process that clubs undertake is a flawed idea.

Having coached two separate teams to grand finals, Roos said that Lyon had proven his credentials and clubs already knew what they were getting after his previous 305 games in the top job.

"The process for Ross has already been done, he's already been through the process. I can understand if you've got Alastair Clarkson and you've got Ross and you're Carlton," Roos said.

MELBOURNE, AUSTRALIA - NOVEMBER 21: Ross Lyon the coach of the Saints speaks to Robert Harvey the assistant coach during a St Kilda Saints AFL training session at RSEA Park on November 21, 2022 in Melbourne, Australia. (Photo by Quinn Rooney/Getty Images)

"I'm just using Carlton as an example, I'm not saying Michael Voss isn't going to be a good coach. Vossy had a fantastic season. But we know what Ross brings.

"I've been through it, I've seen guys do powerpoints, anyone can do a powerpoint, everyone can talk about game style. It's the ability to get it out of your head. Ross' process has been coaching St Kilda and coaching Fremantle, so the process has already been finished for Ross."

Essendon underwent a process but seemingly strayed away from it at the final moment to appoint former North Melbourne coach Brad Scott. Scott hadn't been involved in the original interviews that saw Adem Yze emerge as the reported favourite candidate, but was soon ushered in to be appointed in the senior role position.

Roos made note of that, questioning why the Bombers wouldn't be keener on Lyon given the abandonment of their own process.

"But honestly, it's (coaching processes) garbage," Roos said.

"Look what Essendon did, they went through a process, had one conversation with Brad Scott, and gave him the job. He didn't go through a process."

Watch the full interview on Zero Hanger TV: