EA and Valve are currently engaging in late negotiations in an effort to bring Battlefield 3 to Steam, according to claims.
BF3blog quotes an ‘anonymous source from inside Valve' as claiming the game should see release on the service alongside its US release on October 25th.
The ongoing stalemate revolves around the sale of DLC. Valve requires that DLC for games sold on Steam is delivered via Steam, whereas EA would prefer to distribute the content via its own means.
In June Crytek shooter Crysis 2 was pulled from Steam for exactly that reason.
EA has been using the dispute to drive consumers to its own digital retail portal, Origin, but there's little doubt that Battlefield 3 will achieve wider penetration and greater sales if also sold via Steam.