Spanish newspaper AS claims Song is considering quitting the Nou Camp club in January after falling out of favour under Tata Martino - and Manchester United have been linked.
The former-Arsenal midfielder has found first-team opportunities hard to come by since swapping north London for Catalonia.
And the report, carried by the Daily Mirror, claims he's reconsidering his future at Barcelona after playing just 15 per cent of the club's minutes this term.
Song has featured in just 91 minutes out of a possible 630 this season - his one start came in the 1-0 win over Malaga but that was an enforced change after Sergio Busquets was ruled out through injury.
Barcelona's experiment with Song at centre-back was much less successful than the club's deployment of Javier Mascherano in a similarly converted midfielder-to-defender role.
And if he becomes available in the January transfer window, United could rekindle their interest.
David Moyes was linked with several midfielders over the summer transfer window - including Song - but United signed Marouane Fellaini from Everton on deadline day.
Song, though, was identified as a potential holding midfielder for United with Fellaini expected to make more of an impact in the opposition's box.