The French midfielder played for Arsenal between 1996 and 2005 before joining Italian giants Juventus.
He then moved to Juve's rivals Inter Milan but was linked with a move back to the Premier League after enduring an injury-plagued campaign last season.
Tottenham Hotspur were credited with an interest in Vieira but Wenger does not believe that the 33-year-old could join Arsenal's London rivals.
"There is a football decision and there is a psychological impact on a player of that stature that could come in," the French manager was quoted as saying by Sky Sports.
"But at the moment we need to look at the level of experience in your squad to make this kind of decision.
"We are nowhere near to making a decision like that, but it is a possibility.
"We do not rule it out and we do not say we will do it - and that is my decision at the moment."
Arsenal have already lost two high-profile players in Kolo Toure and Emmanuel Adebayor, who both joined Manchester City.