See below for update. Despite the fact that the sitcom has been a winner for CBS in the Thursdays at 8:30pm timeslot, it looks like Rules of Engagement has been cancelled.

An inside source has told us that CBS has decided not to order the back nine episodes for the current sixth season. The cast and crew have two episodes left to shoot and believe that those will be the last episodes of the series.

Our source tells us that calls went out on Friday night to those who work on the show to give them the bad news. Especially given the current ratings, many were understandably shocked and upset as they head into the holiday season.

Starring David Spade, Patrick Warburton, Bianca Kajlich, Megyn Price and Oliver Hudson, Rules of Engagement launched in early 2007 and has been a reliable pinch hitter for CBS for years. It started in the post-Two and a Half Men timeslot but has been moved to a couple different timeslots.

Last May, the series was renewed for a sixth season with the aim of a Saturday night run. Word was that the studio gave CBS a great deal so they’d have additional episodes for the syndication package. When How to Be a Gentleman tanked, the network brought Rules back to Thursdays where it’s doing far better than it did last year — and better than any other sitcom that CBS has had in that coveted slot.

Our source says, “The reality is it’s got to be politics. The network has always had it out for Tom [Hertz, Rules’ creator] and the show, which is why it’s weird that they just set up a put pilot with him for next season… It really does seem to be a desperation move on their part to find something that hits it out of the ballpark in that Thurs 8:30 slot. Doubles and triples apparently aren’t good enough for them. They’d rather risk a few more fouls and strike outs than go with a solid player.”

What do you think? Are you a fan of the TV series? Should it get a seventh season?

UPDATE: A network source has told us that Rules has not been cancelled — not yet anyway. Apparently the sitcom was picked up for 18 episodes for season six, to be combined with two leftover episodes from season five. CBS has now cut the episode order down to 13 episodes (or 15 total). (Deadline is now reporting the same thing.) While the door is still open for season seven, we’re told that many involved with the production believe this is truly the end of the show.

Image courtesy CBS.