Season four of Heroes has, already, got off to a bit of a bumpy start. While the latest episode apparently lifts things a little, the season opener was met with a muted reaction (and our own James Hunt wasn't overly convinced by it either), and the hope that the show had this time got the magical shot in the arm it's been needing has already begun to fade.

The history of Heroes to this point is, of course, well known. Season one: great. Season two: not great. Season three: generally not great. The hope was that the return of Bryan Fuller to the show would turn things around, but he's now left Heroes for a second time, and there's a fear that the show will never be able to convincingly recapture the momentum and quality of its opening run.

Worryingly for NBC, audiences now seem to be deserting the show, prompting fresh fears over just how many lives Heroes has left. It's believed to be the international audience, its DVR catch up audience and sizeable DVD sales that led to NBC commissioning the fourth season of the show in the first place, in spite of the hardly-positive reaction it was attracting.

Yet the season opener generated ratings of just 6.11 million viewers in the States, its lowest season opening thus far. A year ago, it snagged 10 million viewers for the opening episode (and at one stage in its life was up to 16 million), and this week's episode, Redemption, has fared little better. According to the latest Nielsen Co numbers, its ratings for the latest episode were worse than the first hour of its season premiere, but better than the second. That still sees the show as having lost around a quarter of its audience, though, and those are the kind of numbers that NBC is going to struggle to sustain.

It's not the only show struggling with the new season, to be fair. Fringe, Dollhouse and Lie To Me are all having a tough time, leading to suspicions that each of those is unlikely to earn another series run once this one is done. But for Heroes, a show that's seemingly effortlessly survived, the fear now is that if the ratings follow the current pattern, that NBC will have no choice but to can one of the most expensive shows to make currently running.

With the general reception to season four being that it's showing a bit more potential but still making lots of the same mistakes as it has in recent times, Heroes' glory days now seem a long way behind it. And in the months ahead, it's facing an almost-impossible battle to get a fifth season commission.

Here's hoping the show does manage to turn things around, but we're not holding our breath...