Adam Ashley-Cooper returns on the left wing, after featuring in that position against Fiji recently, and then last Saturday when he returned from an ankle injury during the second Cook Cup match against England.
Luke Burgess resumes in the number 9 jersey after Genia broke his thumb against England Sydney last weekend.
Kurtley Beale and Josh Valentine will return to the matchday squad, taking the places of Ashley-Cooper and Burgess respectively on the replacements bench.
While Australia's 21-20 loss to England did not prevent the retention of the Cook Cup, which had been secured by the Wallabies' 27-17 win over the English in the opening Test in Perth, Deans says the side took no solace from collecting the trophy at ANZ Stadium.
"We let ourselves down. There were reasons why we came up short and it is critical that we rectify them," he said.
"Certainly anyone who watched the two Tests against England would appreciate that the urgency that was shown by our players during the match in Perth wasn't replicated to the same level last weekend."
Nor is Deans reading too much into Ireland's two recent defeats, in New Zealand, to the All Blacks and New Zealand Maori.
"They had a man sent off early on against the All Blacks, which is not something any side can afford, and suffered accordingly," he explained.
"They did score four tries in that match, and got them all while playing with 14 men, which is a fair indicator of their willingness, in terms of having a go. It also says a lot about their capabilities."
This is Australia's first meeting with Ireland since a late try from Brian O'Driscoll earned the Irish a 20-20 draw with the tourists at Croke Park last November.
"They are a seasoned unit, with proven performers in the key positions. Our recent matches will also have given them plenty of confidence that they can succeed, while their players will be hungry," added the Australian boss.
"This is their last match before a summer break, and a win on Saturday night will make this tour a success from their perspective.
"As we saw last weekend with England, that combination can be a powerful motivator so anything less than a significant improvement from where we left off in Sydney will not be good enough."
The Australian team will once again be captained by former Leinster flanker Rocky Elsom who is one of four surviving members from the Wallaby side that started against Ireland in Melbourne two years ago.
Ashley-Cooper, Burgess and Matt Giteau were also in the starting line-up for the 18-12 win over the Irish, in what was Deans' first Test match in charge.
AUSTRALIA TEAM & REPLACEMENTS (v Ireland, Lansdowne Cup Match, Suncorp Stadium, Saturday, June 26, kick-off 8.05pm local time/11.05am Irish time):
15 - James O'Connor (Western Force)
14 - Drew Mitchell (NSW Waratahs)
13 - Rob Horne (NSW Waratahs)
12 - Matt Giteau (Brumbies)
11 - Adam Ashley-Cooper (Brumbies)
10 - Quade Cooper (Queensland Reds)
9 - Luke Burgess (NSW Waratahs)
1 - Ben Daley (Queensland Reds)
2 - Saia Faingaa (Queensland Reds)
3 - Salesi Ma'afu (Brumbies)
4 - Dean Mumm (NSW Waratahs)
5 - Nathan Sharpe (Western Force)
6 - Rocky Elsom (Brumbies) (capt)
7 - David Pocock (Western Force)
8 - Richard Brown (Western Force)
16 - Huia Edmonds (Brumbies)
17 - James Slipper (Queensland Reds)
18 - Mark Chisholm (Brumbies)
19 - Matt Hodgson (Western Force)
20 - Josh Valentine (Brumbies)
21 - Berrick Barnes (NSW Waratahs)
22 - Kurtley Beale (NSW Waratahs)