Song left Arsenal for Barcelona in 2012 after making 215 appearances in seven years for the Gunners.
He struggled to break into the first team at the Nou Camp and returned to England in 2014 with West Ham before joining Russian side Rubin Kazan in 2016.
But the Cameroon international is looking for a new club after the players were not paid for four months.
And on transfer deadline day, Song posted a picture on Snapchat of himself wearing an Arsenal training top with the caption: “No pain, no gain.”
It is unclear whether Arsenal are looking to resign Song but his presence at the club could lead to a deal being done due to being a free agent.
And some Arsenal fans on Twitter think a move for Song would boost the team.
James Stokes wrote: “I’d take Alex Song for 6 months. Providing it’s not the Alex Song that starting trying diagonal passes every game and thought he was Rivaldo. Seeing as we sold our only DM, he’s the best we’ll do with the time we have….”
Jack Webster said: “Alex song training at Arsenal. Currently I’d take that.”
And Den wrote: “Imagine Alex Song with bleached hair pinging passes over the top for Aubameyang & Lacazette to run on to at Arsenal in 2018.”
In 2014, Song explained why he couldn’t turn down a move when Barcelona came calling.
He said: “I had been there a long time but won nothing. Every year, we lost our best players.
“Cesc, Robin (Van Persie), Samir (Nasri). If the club had kept everyone, Arsenal would have been champions during that time.
“Then I had the chance to go to Barca. And you don’t turn that down. You only get that chance once.”