Wallabies great Andrew Slack believes Robbie Deans should be honest and explain that Quade Cooper's controversial omission from his Test squad to face the British & Irish Lions is due to last year's "toxic" outburst. And Slack warned the under-pressure Wallabies coach that he needed to forgive and forget quickly if he wanted to beat the Lions - and hold onto his job.

Australia's 1984 Grand Slam-winning skipper labelled Deans a flawed selector and said the "flimsy" reasons the coach gave for the 38-Test first five-eighth's non-selection had failed to hit the mark. Deans pointed to Cooper's suspect defence, his positioning at fullback for Queensland Reds, a reluctance to take contact in attack, and an over-abundance of offloads, as reasons for his decision to omit the playmaker. He also partly blamed Cooper's attacking shortcomings for the form dip of teammate Ben Tapuai.

"The truth seems to [Deans] wanted to leave Cooper out because he doesn't trust him to do what the team requires," Slack wrote for ninemsn. "He probably should have said that, rather than blame Ben Tapuai's below-par form in 2013 on Cooper. The hurt and disappointment from the notorious 'toxic' tweet of last year [describing the Wallabies camp] clearly still burns Deans, but for the sake of the team he needs to get over it.

"There is no doubt Deans gave Cooper a lot of support early in his career, but I believe he has run out of patience too soon, and the exclusion of Australia's most talented fly-half may well end up costing the coach his own job. "Ask the Lions who they would least like to be wearing the Wallaby No.10 shirt, and it would be close to a unanimous vote for Cooper."

Slack joins the likes of former Wallabies coaches Bob Dwyer, John Connolly and Eddie Jones as well as Test greats Michael Lynagh and Tim Horan who have all backed Cooper strongly as the best playmaking candidate despite his weaknesses.

Deans can still include Cooper in his final 31-man squad when he adds six more players on June 11.

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