I think there is always going to be rumours, but he himself isn't the youngest any longer, if he joined for 2012, I wouldn't expect him to manage 3 seasons, so I guess if teams want continuity for a period of time he's not the best option. If Heidfeld's position is under threat, as Renault have hinted, I imagine he is on a very short term contract, so maybe he could jump in there if he wanted to, but I think he turned it down in January, and is now part of another racing series, so maybe not. Also, I doubt he'd want to race for anyone but a top team, although his career has gone off on a bit of a tangent recently, so maybe that doesn't bother him so much now?