The Belgium international fell out of favour at the Emirates Stadium last season as Laurent Koscielny and Per Mertesacker were preferred in the heart of Arsenal's defence.
With Louis van Gaal seeking to bolster United's back line following the departures of Rio Ferdinand and Nemanja Vidic, Vermaelen has been a reported long-term target for the Old Trafford club.
Wenger confirmed there had been offers made for the 28-year-old and strongly hinted that Manchester United were among his suitors.
Asked if there were offers on the table for Vermaelen, the Frenchman responded: "Yes, I can't tell you [who] but you will know very soon.
"I think [Manchester United] could be in the group. It could happen, I said that since the start of pre-season.
"We're in a position where it's difficult to stand in his way. We never speak about the price."
Wenger also confirmed his World Cup-winning contingent will return to the club on Monday - a day after Arsenal take on Manchester City in the Community Shield.
Mesut Ozil, Lukas Podolski and Mertesacker will also miss Arsenal's Premier League opener against Crystal Palace on August 16.
"It's not ideal but the final of the World Cup was on July 13 and they went back to Germany, where they lose a few days in celebration," he added.
"After having the experience of winning a World Cup, it's always difficult to come back mentally and be sharp and hungry straight away.
"They have a [training] programme they follow so [their return] could be very quick."
