Seven Juve players started last month's 2-0 home win over Bulgaria, the world champion's best performance in months which left them one point shy of qualifying as Group Eight winners, and the same number could feature in these last two matches.
"It is the most important week of the last two years," Italy coach Marcello Lippi told a news conference, referring to Saturday's test against second-placed Ireland and the visit of already eliminated Cyprus four days later.
"It is very important to qualify on Saturday. Not only from my point of the view. It's important for everybody."
Italy captain Fabio Cannavaro is suspended for the trip to Croke Park so Nicola Legrottaglie, also Cannavaro's deputy at Juventus, is likely to step into central defence alongside another club team mate Giorgio Chiellini.
After the recent failure of 4-3-3, Lippi's diamond midfield was big a success last month and he looks poised to keep the formation, with in-form Daniele De Rossi likely to keep out the returning Gennaro Gattuso.
Ireland, unbeaten in their campaign so far, hold a five-point lead over third-placed Bulgaria and are favourites to seal the group's playoff spot even if they cannot match the draw they picked up in Italy six months ago.
Their path to next year's finals in South Africa became more difficult when FIFA decided last week to seed Europe's World Cup playoffs according to rankings but Trapattoni was confident his side could compete against top opposition.
Ireland, ranked 38 in the world, are unlikely to be seeded for November's playoffs and could face the likes of France and Germany should they not win their respective groups.
"We have to realise that business is business and so it is not such a surprise that this happens when the big teams are not all at the top of the table," Trapattoni told a news conference.
"(But) for me it's not important because we can play against any of these teams and we will show that on Saturday against the world champions."
Fulham winger Damien Duff will join fellow midfielders Steven Reid and Darron Gibson on the sidelines on Saturday after injuring his calf but Trapattoni hopes a further scan will clear the 30-year-old for Wednesday's match at home to Montenegro.
Ireland: 1-Shay Given; 2-Sean St Ledger, 3-Kevin Kilbane, 4-John 0'Shea, 5-Richard Dunne; 6-Glenn Whelan, 7-Aidan McGeady, 8-Keith Andrews; 11-Stephen Hunt; 9-Kevin Doyle, 10-Robbie Keane
