There is major concern over Douglas with a call on his fitness expected to be made after Australia's match with England at Twickenham on Saturday.
"We've got what we need for this (England) game, obviously Dave (Dennis) can cover that area," Deans said.
"We need to monitor Kane's progress. It's possible we could call for two replacements. We've got to get through the weekend obviously.
"We'll do it as soon as it's evident. If the medical staff believe it's marginal whether he'll be available to us next week, we'll probably have to act."
The International Rugby Board judiciary panel hit Simmons with the surprisingly heavy ban in London on Wednesday for his tackle on French flanker Yannick Nyanga in the second half of the Australia's 33-6 loss to France last weekend.
Simmons' ban, which can be appealed, is for eight 'active' weeks and will keep him sidelined until February 24.
The Wallabies are yet to decide if they will appeal the ban and it's believed they have until Friday to do so.
"We're disappointed in the decision but I haven't had the opportunity to read the decision yet and obviously we'll do that before we settle on whether that's the end of the matter or not," Deans said.
"There is the potential to appeal but we'll have to consider his decision, the wording of it, the transcript of it ... it's not something we would do lightly."
In further bad news for the Wallabies, inside centre Pat McCabe was ruled out of the side to face England with a neck injury with Deans set to reshuffle his backline.
Ben Tapuai or Adam Ashley-Cooper could be shifted in to play at inside centre for the injured McCabe.
- AAP