A topsy-turvy week — emphasis on the turvy — at NBC ended with Christina Applegate departing Peacock NBC sitcom “Up All Night” and midseason drama “Do No Harm” getting pulled from the schedule after its second airing.

In addition, struggling freshman Thursday comedy “1600 Penn” is being preempted this week in favor of an expanded edition of “The Office.”

NBC execs anticipated the network would hit a rough patch this quarter with “Sunday Night Football” over and “The Voice” taking a breather until late March, but bizzers are still surprised at how low the ratings have been for midseason entries and declines for new programs that looked promising, like “Go On.”

NBC’s outlook for this season and beyond has changed rather significantly in the past seven days. While Thursday’s season-four premiere of “Community” — the first episode without series creator Dan Harmon — drew a respectable 1.9 rating among viewers 18-49 and even topped Fox’s “American Idol” in male viewers 18-34, Tuesday’s season-two premiere of “Smash” collapsed to a 1.2, while “1600 Penn” (1.1) and “Do No Harm” (0.7) performed even worse.

“Do No Harm” dropped 22% compared with an already low series preem. The modern “Jekyll and Hyde” medical drama bowed Jan. 31 at 10 p.m. to a 0.9 rating and 3.1 million viewers overall, making for one of the lowest series debuts of all time across the four major broadcasters.

Thursday’s second episode pulled only 2.18 million viewers, sealing its fate. In the short term, NBC will replace previously scheduled episodes of “Do No Harm” on Feb. 14 and 21 with encore broadcasts of staple procedural “Law & Order: SVU.”

Also dropping from its previous series low was “1600 Penn,” which drew a 1.3 rating and 3.3 million viewers Jan. 24. The comedy stars Josh Gad, Bill Pullman and Jenna Elfman. Meanwhile, “Community” topped its season-three premiere by 12%, even though it had to face “Idol” this time around.

Though many have assumed that “Community” will not last past this season, it suddenly stands as NBC’s second healthiest Thursday candidate for renewal, behind “Parks and Recreation,” which had its highest rating in the demo since November 2011 (2.0). NBC also has freshmen “Go On” and “The New Normal” on Tuesdays and “Whitney” and “Guys With Kids” on Wednesdays. On the Peacock bench is the yet-to-premiere “Save Me,” starring Anne Heche; the show produced two episodes and then put production on hold following a change in showrunners.

NBC had no immediate comment on whether Applegate’s exit would derail future plans for the second-year sitcom “Up All Night,” which the network said in October would abandon its single-cam format for a multi-cam approach. The show went into a three-month production hiatus, with work on the remaining five episodes of 16 in 2012-13 to resume this month in the new format.

In the intervening period, series showrunner Tucker Cawley and creator and exec producer Emily Spivey each exited the show. Will Arnett and Maya Rudolph are the show’s other main stars.

“It’s been a great experience working on ‘Up All Night,’ but the show has taken a different creative direction, and I decided it was best for me to move on to other endeavors,” Applegate said. “Working with Lorne Michaels has been a dream come true, and I am grateful he brought me into his TV family. I will miss the cast, producers and crew and wish them the best always.”

Applegate’s previous broadcast comedy, “Samantha Who,” almost made a similar transition from single-cam to multi-cam. The series had run for two seasons on ABC when the network and ABC Studios in 2009 considered converting the show to a format resembling “How I Met Your Mother” — shot multi-cam over four days without a studio audience — in order to save money. Instead, ABC chose not to renew “Samantha.”