NBC is saving its new midseason guns for after the Olympics, setting premiere dates for "Parenthood," "Celebrity Apprentice" and Jerry Seinfeld's "The Marriage Ref."
Among the premiere dates:
--Drama "Parenthood," delayed by casting changes, will replace "Heroes" Mondays at 9 starting March 1. "Heroes" will have wrapped its run by then, NBC said.
--Seinfeld's reality series, "The Marriage Ref," hits the air on Sunday, March 14, at 8 p.m. It will lead into the new season of "Celebrity Apprentice," which also premieres March 14. The series once again will run as a two-hour block from 9-11 p.m.
--NBC is expanding "Dateline NBC" to two hours in January, after football. It will air Sundays from 7-9 p.m. during the early part of the year. It contracts back to one hour on March 14.
--"The Biggest Loser" will kick off a new season on Jan. 5. It remains in its Tuesday 8-10 p..m. slot.
Not yet announced: A premiere for midseason comedy "100 Questions." The series recently had its order cut to six episodes. NBC also has yet to schedule the celebrity genealogy show from producer Lisa Kudrow.