Wenger came into the season with four recognised central defenders but with Thomas Vermaelen still unavailable, Squillaci's absence would leave Laurent Koscielny and Johan Djourou with no cover in case of injury or suspension.
Squillaci picked up a muscle strain during Saturday's 1-1 FA Cup third-round draw against Leeds, when Arsenal needed a last-gasp penalty from captain Cesc Fabregas to keep them in the competition.
Wenger has previously been linked with Bolton's Gary Cahill, while Everton's England defender Phil Jagielka and Werder Bremen's Per Mertesacker were also mentioned during the summer. But it is not yet clear whether Wenger would splash out on a new first-choice defender or look at a cheaper option as cover for this season.
Wenger said: "If we only have two centre-backs then that cannot work with the number of centre-backs we have. If Squillaci has a problem then we must quickly go out for a player.''
With two ties against Ipswich in the Carling Cup coming up, as well as battling for the Premier League and the toughest of European assignments Barcelona, Wenger will not have wanted to add another fixture into their congested schedule by being forced into a replay with Leeds.
However, after again not making the most of first-half chances, notably through Andrey Arshavin, who failed to convert when clean in on goal after 11 minutes, the final outcome against Leeds could have been much worse. Arshavin, and also Nicklas Bendtner, found themselves jeered by some sections of the home crowd after time and again promising moves broke down. Wenger, though, has every confidence Arshavin will soon display the top-class football he is capable of on a regular basis.
"The fans were frustrated. That comes from when you don't win,'' the Arsenal manager said. "The fans are demanding. We were not consistent technically and so they picked on our inconsistencies. It is not through a lack of desire with Arshavin. He wants to do well. He took one touch too many with his first chance and the keeper did well to save another shot he had. Every player during a season has strong and weaker periods and he has had a weaker period, then two or three weeks on the bench.''
Wenger continued: "I have no worries that Arshavin will come back into the team, but their confidence does suffer a little bit from that. We try to analyse our games in an objective way and I am lucky because our players are self critical, they analyse themselves well and they want to do well.''