The move follows Dean Canto's run in the car at Phillip Island, replacing regular driver Ash Walsh.
Davison raced for Erebus in the Pirtek Enduro Cup alongside brother Will, who is having his last outing with the team before departing for Tekno Autosports.
“We have a development plan in preparation for 2016 and beyond, and we are focussed on it,” said Ryan.
“Dean did exactly what we asked of him at Phillip Island, however he doesn't have experience at Homebush.
“Alex, who finished eighth in 2013 when he last raced at Homebush, is the perfect choice for the team's requirements this weekend.
“We are one of three manufacturers who have won races this year, but we need to be a front running team week in, week out.
“Our overall development program reaffirms our commitment to our team, sponsors, and fans.
“We hope that substituting Ash over the last two rounds of the season with experienced drivers will prove productive for our program.”
“I'm excited to get back into a V8 Supercar at a sprint event, as opposed to an endurance event which is what I've been doing the last few years,” said Davison.
“I've driven for Erebus for the past two season in the enduros and I have a really good relationship with the team, so I can't wait to get stuck into the weekend.”