Sullivan is hopeful new boss Slaven Bilic can help Song regain the form he showed at Upton Park in the first half of last season
The former Arsenal midfielder arrived on a season-long loan from Barca last summer and Sullivan is hopeful the 27-year-old will pledge his future to the Hammers after 25 Premier League starts last term.
“I can assure you we have not given up on Alex Song yet,” said the joint-chairman on the club’s official website.
“Before Christmas Alex was outstanding and if we believe we can get him back to that sort of form and maybe with a new manager we can, we would very much like Alex to come.
“We are very thin on the ground with midfielders. You do get injuries and you need back-up. We have got Europe and other games that we want to win.
“There was not enough competition for places last season and this year we don’t want the same again. If the players have a bad game they will have to fight for their position back.”