A final decision would be made after today's captain's run at Allianz Stadium.
"We've got a few options," Rennie said. "Aaron may take them ... or it could be Andrew Horrell, he's been kicking a lot lately and he's very good. If we have some shots from a long distance, Charlie Ngatai is an option. He's got a big boot on him and has been doing a fair bit of goalkicking as well."
Rennie has made six changes to the team which were well beaten by the Reds. All are an attempt to spark an attacking renaissance in what will be a tough encounter tomorrow night.
"On paper they're one of the best teams in the competition," Rennie said of the Waratahs. "They've got a lot of Wallabies and firepower in the backs. They'll be a handful if we allow them any space.
"We'd be incredibly disappointed if the response isn't critical in the weekend. It's a tough competition but we didn't quite get it right and we got punished for it. We created a hell of a lot of opportunities but didn't finish."
The midfield switch of Richard Kahui to second-five - replacing Bundee Aki - and Ngatai to centre is one attempt to create something, as is the naming of Horrell ahead of Anscombe.
"Gareth's still learning the role at fullback. He's done a really good job and his goalkicking has been fantastic. But again, we've got some pretty good players who have been sitting on the bench watching and it's a long competition. Hozza played a lot at fullback last year and did a pretty good job and we think he'll give us a bit of spark back there.
"We've also had probably three weeks where we've created opportunities but haven't scored so we're looking for a change ... to give us a bit of spark."
Halfback Brendon Leonard replaces Augustine Pulu for his first start of the season. In other changes, prop Pauliasi Manu returns from a knee injury, replacing Toby Smith at loosehead, and Lelia Masaga returns from a back injury to the right wing.