The 80-Test playmaker moved into a coaching role with Osaka-based club Kintestu Liners last season, leading to the assumption the 38-year-old had called time on his playing days.
But Cooper has made clear he never retired and has added his name to a list of veteran playmakers that also includes Bernard Foley and James O'Connor in the mix for one last hurrah.
Foley will play for the NSW Waratahs next season, while O'Connor has been linked with a return to the Western Force.
Declan Meredith will wear the No.10 against Japan on Saturday, with Ben Donaldson on the bench and Carter Gordon overlooked after recovering from a leg injury.
There is also Tom Lynagh at the Queensland Reds attempting to regain fitness and new Wallabies coach Les Kiss, while not keen to tinker greatly in the halves, won't guarantee anyone a jersey.
As it stands Cooper has no playing contract for next season, a major spanner in the works ahead of the World Cup in Australia from next October.
But Wilson said Cooper, whose last Test was in 2023, could never be written off.
"It was good to have Quade in, a Wallaby legend and a lot of the boys' heroes," the skipper said.
"He was talking about the conditions ... having him around the group was awesome.
"Physically he's still capable, (but) he's got to start playing again.
"Unbelievable talent; his knowledge is unbelievable. I've not doubt he could still do it, but he's not signed at the moment for next year so it could be tough, but you never rule out Quade."
The Wallabies will meet more familiar faces in Osaka on Saturday night, with former Reds lock Harry Hockings one of three expats named for Japan.
The 28-year-old debuted for Japan last year, earning eligibility after leaving Australian rugby following a stand-off over a competition-wide 60 per cent pay reduction during the pandemic.
His exit, alongside Isaac Lucas and Izack Rodda, wasn't well received at Ballymore at the time.
"I grew up with and Hocko, I'm really good mates with him, went to his wedding a couple of years ago, so can't say there's any anger there," Wilson said of their relationship.
"He's been over here quite a while, bought into everything Japan's about ... but you want to get one over him."
Wilson said Kiss had kept things calm this week, but expected an emotional address before kick-off.
"We know we need to win; we want to be a consistently-winning team and there's no excuses with a new coach coming in," the captain said.
