Cesare Prandelli's are four points clear of Friday's second-placed opponents in Group B, with the pair unbeaten so far in their campaign.
Wins against Bulgaria on Friday and the Czech Republic on Tuesday would put them on the brink of a place in Brazil where they can make amends for their poor showing in South Africa three years ago where they failed to win a match and were eliminated at the group stage.
Prandelli, who is the subject of reports in Italy that suggest he will leave his post after the World Cup next year, will be without the key trio of Mario Balotelli, Pablo Daniel Osvaldo and Riccardo Montolivo due to suspension.
However, the 56-year-old is more concerned that Bulgaria could be in better shape than his side, with the domestic league already seven games in, compared to Serie A where only two game weeks have been completed.
"I am worried above all, about the physical conditions," he said on Monday.
"Bulgaria is in good shape, they can give us some problems. We have to contrast Bulgaria with lots of quality in the middle of the field and with lots of running along the touches.
"Bulgaria is in good physical condition, it will be a difficult match and historically we have always had problems in September. The message is thinking about winning these two matches before talking about the World Cup."
Italy stalwart Gianluigi Buffon could equal the all-time appearance record of 136 caps for his country against Bulgaria at the Stadio Renzo Barbera.
Buffon was part of the side that won the World Cup on penalties in 2006 and he believes representing his country means as much now as it did when he made his debut in 1997.
"There is a sense of honour when you represent your country," he explained.
"You understand that with time, with maturity. Every appearance with the national side is not just a game, but something more.
"I personally would not turn down a call up. It would be like spitting in the face of good fortune, something that so many people want but only a few have the chance to experience."
In contrast, Lyuboslav Penev has called up uncapped goalkeeper Georgi Kitanov into his 21-man squad.
Penev has seen his side's campaign falter somewhat in recent matches, drawing four of their six qualifiers.
However, he will take heart from the 6-0 win over Malta in March as well as the 2-2 draw with Italy in the reverse fixture.
His side also remain in pole position to secure a play-off place, sitting a point ahead of the Czech Republic in third.
