Deans decided to send his star fly-half back to Queensland Reds to get his form and fitness back after seven months on the sidelines with a knee surgery, but saw his Wallabies side beaten 9-6 by Scotland on Tuesday.
Despite that failure - a first home defeat to the Scots since 1982 - Deans does not plan to rethink his position on Cooper. He said: "There is no chance of bringing Quade Cooper back into the squad."
He added: "It's not worth the risk and it would be negligent, it could compromise him and possibly the team."
Deans gave Berrick Barnes his first start at number 10 under his regime in Newcastle and watched as the Waratahs pivot failed to unlock the Scottish defence despite 35 minutes spent camped in their territory in the second half.
Deans knows they must be better this time against a Wales side who promise to bring an even stiffer challenge than their Six Nations opponents.
"We knew what this week was going to be like and we gave a lot of thought to our combinations. Even so, we came up short in the first instance," admitted Deans.
"Our plans for the weekend started the moment the final whistle blew on Tuesday night and we know there are significant areas of our game that will have to improve.
"If any of the Australian players had forgotten what Test rugby is like it is looming large in their minds now. The players are back in the groove of Test rugby and face a massive game on Saturday."
The full Wales squad, led by stand-in head coach Rob Howley, trained for the first time together on Wednesday and have no injury worries. The 16 players who headed to Brisbane before the win over the Barbarians last weekend are likely to form the bulk of the starting XV to open the series at the Suncorp Stadium.