The first of the three internationals against Robbie Deans' troops is just nine days away now but Gatland says people shouldn't read too much into who runs out at the Allianz Stadium this weekend.
"We haven't even spoken about the first Test in terms of that. These players have got an opportunity on Saturday," said Gatland.
"Some players have had two or three games in a week. We've got to think about Tuesday - we've got a game against the Brumbies on Tuesday - and we're still looking at combinations.
"We said to the players that there's an opportunity for the players on Saturday to stake claims but the Test team won't be selected until after Tuesday.
"We've got a few knocks in the backs at the moment. We need to make sure that we rest a few players because the whole priority is making sure that we arrive in Brisbane next Saturday fresh and ready to go.
"We don't want to pick up any more knocks or injuries. A few players are coming back, which is good. We've got almost a full complement of forwards, which is great, but the backs have tended to take most of the punishment, probably because of the way we have been playing.
"We have been moving the ball a lot and playing a heck of a lot of rugby, and some of the metreage that some of our backs have covered and the amount of work they've done, it has taken its toll a little bit."
Competition for a Test place appears stiff throughout the squad but perhaps nowhere more so than in the back row, where skipper Sam Warburton is selected at openside flanker for his second game of the tour, with Tom Croft and Jamie Heaslip joining the Welshman against the Waratahs.
Dan Lydiate provides cover from the bench, with Toby Faletau, Sean O'Brien and Justin Tipuric not featuring having all had game time on Tuesday.
Gatland admits that he faces a tough call as to who to name at No6, 7 and 8 at the Suncorp Stadium a week on Saturday, again re-iterating his stance that his players still have it all to play for in the next two games.
"We have far from made up our minds about the loose forwards (for the first Test)," added Gatland, who expects a big battle, particularly up front, from the Tahs.
"There is a huge amount of options and combinations. They are all fit at the moment, and all of them have done really well.
"That is going to be one headache, and the next couple of games will determine it.
"I was impressed with the Waratahs against the Force (last weekend). Their breakdown is excellent, they are a really good outfit.
"They are missing a few players, but to go to Perth and win that game would have given them a huge amount of confidence.
"They had a poor start to the season by their own admission, but they look as though they are getting better as the season has gone along."
For the full Lions side to face the Waratahs on Saturday, please click here