"Dave Dennis coming back in for the Waratahs will bolster their line-out for tomorrow. He's a good player and he has got some Test experience," said Rowntree.
"We had a few issues in the line-out on Tuesday night. We dropped three from 16, but a lot of that was just personnel that hadn't played a lot together.
"That's what you get on a tour like this. You take it on the chin and move on. I actually thought they battled very well as a pack on Tuesday night. They didn't really get enough credit for the performance they put in."
Rowntree and his fellow coaches are still undecided on the make-up of the team to take on the Qantas Wallabies in next weekend's opening Test in Brisbane and Saturday's game with the Waratahs, along with Tuesday night's clash with the Brumbies in Canberra, will be the last chance for players to make a push for a coveted test jersey.
"It is not getting any easier in terms of selection. There are a lot of guys putting their hands up. We will get tomorrow out of the way, and then tomorrow, and then we will pick a Test team - that is the truth," said Rowntree.
"Richie Gray got a bump on his shoulder and certainly wasn't fit for this weekend, but we are hoping he is going to be fit for Tuesday. At this stage, I am counting on him being fit for Tuesday."
All the players were told they would have to fight for a Test place even before the tour started and Rowntree insists nothing has changed. That includes the tour captain, Sam Warburton, who leads the side for the second time in Sydney.
"I have been very impressed with him. He's very professional and e is certainly not showing any signs of stress or pressure. Like all the other players, he goes about his business," added Rowntree.
"I have been really impressed with him as a person. He is a doer, and a lot of guys are following his lead in terms of his attitude to training, his diligence."