Following series-low ratings last week, the future of Heroes is more questionable than ever.

Will the once-popular series make it past its current season?

Based on a recent Twitter post, star Greg Grunberg doesn't seem to think so. The actor wrote to fans:

"Winding down shooting Season 3 Heroes. Tough to say goodbye to crew not knowing if any or all of us will return next year. Hope all."

The New York Post reports that Grunberg later caught himself and Twittered again: "Don't get me wrong, Heroes IS coming back next year, but some crew take other jobs, so it's tough."

Considering the immense cast, unusual locations and use of special effects, it's difficult to see how NBC can justify keeping Heroes on the air if it continues to garner such pitiful ratings.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.