The Cameroonian midfielder has been one of the Hammers' most prominent stars this season, with his performances earning him a number of admirers, but doubts have been cast over a move.
West Ham are reportedly reluctant to offer Song the opportunity to stay permanently unless he can regain his early-season form, and that seems surprising considering their desire to capture him earlier in the campaign.
Sam Allardyce has spoken on a regular basis of his desire to complete a transfer for Song, but it was always thought that it would be the player's unwillingness to join on a long-term deal that would block the move.
It was reported in January that Song would only sign for West Ham if they were able to get European football, as he doesn't want to make too much of a step-down from Barcelona.
However, it seems now, rather shockingly, that it is the Hammers who are behind the deal not being processed, and that throws the transfer into fresh doubt.
Song is due to return to the Nou Camp at the end of the season and West Ham will have to spend wisely to cover for his absence, if they do opt to go down alternative routes.
It seems, therefore, that the Hammers might be well served by remembering the old adage: form is temporary but class is permanent.