Update: Additional info via Variety:
Wells and Warner Bros. intend to shop the show to other outlets.
"I'm disappointed that NBC no longer has the time periods available to support the kind of critically acclaimed series that was for so many years a hallmark of their success," Wells said in a prepared statement. "We remain extremely proud of 'Southland' and are actively looking for another home for the series."
NBC said it will do its best to air the episodes that have already been shot and that the quality of the show wasn't a factor in the decision. The show is in the middle of shooting its sixth episode.
Southland has been canceled with production being shut down after six episodes according to the Hollywood Reporter. NBC will continue to air Dateline on Fridays at 9pm.
I was a bit surprised by the quick renewal by NBC of the Warner Brothers produced show in May, and I am a bit surprised that it has been canceled before the second season premiere. After screening the early episodes NBC found them "too dark and gritty" for broadcast, particularly at 9pm.
No word on when/if the six episodes that were already filmed will air.
Friday is a night some believe has less competition for The Jay Leno Show, but Friday night is a night of less viewers on broadcast too. Last Friday, The Jay Leno Show only had a 1.4 adults 18-49 rating out of Dateline's 1.8 rating. Though I do not blame Jay Leno for global warming and everything else wrong in the world, it is certainly conceivable that NBC was worried Southland would provide noticeably less of an 18-49 lead-in than Dateline.