The ex-Arsenal man has only spent two seasons at the Nou Camp after leaving the Gunners, but his time at the club already looks to be coming to an end.
Song has struggled to hold down a first-team berth, and with Barca set for a summer of upheaval his future appears to be bleak.
This has alerted United and Liverpool, who are keen too land the 26-year-old.
Despite him having cost £16m in 2012, the duo are looking to pay close to £8m to lure him back to the Premier League, and are hopeful that the Catalans will accept to get him off of their books.
Arsenal have also been linked with the Cameroon international, who has already admitted that if he leaves Barca he will return to England:
“If I leave Barcelona it will be to return to the Premier League.
“I will return to England one day, that’s for sure.”
Song carved out a reputation as a good holding midfielder with Arsenal, and has been known to play as an emergency centre-back.