The not-yet-official Hollywood writers' strike has already claimed its first casualty: "Heroes: Origins," the planned anthology spun from NBC's "Heroes."

The network has put the six-episode series, which was slated to air in the spring, on the shelf -- at least partly in anticipation of a strike, the showbiz trade papers say. The Writers Guild of America's latest contract expired at midnight Wednesday (Oct. 31), and the guild and producers remain at loggerheads over several issues, most notably residuals for DVD sales.

The guild has a membership meeting planned for Thursday night, and its members could walk out as soon as Friday.

"Origins" attracted considerable buzz following its announcement last May. The show would have introduced six new characters into the "Heroes" universe and let the audience decide which one would stick around for the following season. Several big names were attached to the project -- Kevin Smith ("Clerks," "Dogma") and Eli Roth ("Hostel") were set to write and direct episodes, and "Superman Returns" co-writer Michael Dougherty was writing a third.

In addition to strike fears, NBC is also staring at fan dissatisfaction and a slight ratings slump for "Heroes." Critics and others have attacked the show's somewhat sluggish pace to start the season, and overall ratings are down a bit from last year, even with DVR usage factored in.

For all that, though, "Origins" isn't completely dead. The project could be revived for next season, but NBC didn't want to commit to it financially while facing the possibility of writers not working, the trades report.