This season, NBC had nine drama series debuting in September through late fall, three of them new (plus limited series Heroes Reborn). The network has already renewed eight drama series for next season, with one more, The Mysteries of Laura, on the bubble. It is pretty clear that not all returning NBC drama series would make it on the fall schedule. That may include for the first time veteran Grimm, whose initial Season 6 order is for 13 episodes, not the customary 22, I have learned.

That is not a fixed number, as I hear the pickup is for a minimum of 13 episodes, with a likelihood for more. The move was made to give NBC brass scheduling flexibility. Of the renewed dramas, Jennifer Lopez’s Shades of Blue is a 13-episode order; that is how the show has been set up, as are most heavily serialized starring vehicles on TV, including The Following, How To Get Away with Murder and Aquarius. But the rest are shows that have been doing full seasons: the three Chicago series (the newest, rookie Chicago Med, produced 18 episodes because of a late launch), Law & Order: SVU, The Blacklist, Blindspot and Grimm.

Grimm, whose first five seasons consisted of 22 episodes each, had been the little engine that could, an under-the-radar show that became a breakout during the 2011-12 season, despite airing on Fridays. This season, the supernatural procedural is averaging a 1.6 most current adults 18-49 rating and 6.1 million viewers. That is down from last season’s averages (2.0, 7.1), but Grimm still ranks as one of the highest rated scripted series on Friday despite being a self-starter, with very little lead-in support. It also is owned by NBC and does well internationally, something that plays more and more into networks’ renewal decisions.

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Except for 2012 when it launched following the Summer Olympics, Grimm has been starting late, with a premiere date around Halloween. Its final Season 6 episode count will depend on when it debuts and how many episodes it can run in a row.