The Comcast-owned network made a surprise comeback in the final months of 2012 after years in the ratings basement. The network's viewership jumped 24 percent among the 18- to 49-year-old age group that advertisers crave, the only increase among the four major TV broadcast networks.
Critics are skeptical of whether NBC can stay on top of its competitors through the rest of the TV season. The NBC schedule received a boost in the fall from "Sunday Night Football," singing competition "The Voice," and new drama "Revolution." NFL football games are gone from NBC until next fall, and "The Voice" and "Revolution" will not return until March 25.
Greenblatt said he was "totally prepared" for NBC ratings to decline in the coming weeks. "I think it's inevitable," Greenblatt told reporters at a meeting of the Television Critics Association.
He said NBC had a "very robust" mid-season plan that includes new shows such as "1600 Penn," a comedy about a First Family living in the White House; soapy "Deception" about a murder in a wealthy family; and "Do No Harm," a thriller about a neurosurgeon.
"I'm hoping that out of this new crop of shows we'll get lucky," Greenblatt said.
He said he decided to keep "Revolution" off the air until late March, rather than bringing it back in January, so the rest of the show's first season can run without being interrupted by repeats.
"It's a little bit more of a cable model," Greenblatt said. "If you market properly and have the goods, and then you can run them all in a row without repeats, I actually think that's the better long-term play," he said.
When "The Voice" returns, it will have new judges Usher and Shakira in place of Christina Aguilera and Cee Lo Green. NBC also is bringing back Broadway musical drama "Smash" for a second season starting in February.
Greenblatt began his presentation to reporters and TV critics with a litany of ratings numbers from the fall season, many with double-digit percentage gains.
"I'm going to bore you with some statistics," he said, "because I'm not sure when I'm going to have the chance to do this again."
(Reporting By Lisa Richwine; Editing by Tim Dobbyn)