Robin van Persie is set to complete a move to Manchester United and midfielder Song, 24, has been linked with Barcelona.
Asked about the possibility of more signings, plus the departure of Song, Wenger said: "Both can happen."
Arsenal have been linked with Real Madrid midfielder Nuri Sahin.
Song is one of Wenger's longest-serving players, having joined Arsenal as a 17-year-old from French side Bastia in 2005.
He initially joined on a one-year loan deal, before making the move permanent. Song's current contract is due to expire in the summer of 2014.
Meanwhile, Wenger confirmed that Thomas Vermaelen will replace Van Persie as Arsenal captain this season.
"The new captain is Vermaelen and [the vice-captain is] Mikel Arteta," he said.
"We have many potential captains in this team."