NBC announces midseason lineup changes

NBC, sticking with Jay Leno all the way, has set its midseason schedule around the Winter Olympics, an event that should boost ratings for the fourth place network.

Returning series "Chuck "and "The Biggest Loser" will debut before the Olympics, with "Chuck" arriving on Jan. 11 and" The Biggest Loser" on Jan. 5. NBC already is touting "Chuck" as a new and improved action comedy.

NBC's Olympics coverage airs Feb. 12 to Feb. 28. The network will attract more than double its regular audience during those two weeks.

The Jerry Seinfeld-produced reality show "The Marriage Ref" will debut March 14, and will run Sundays at 8 p.m., leading into new episodes of "The Celebrity Apprentice" at 9.

The dramedy "Parenthood" will premiere Monday, March 1 at 9 p.m., following new episodes of Chuck at 8.

"Parenthood," inspired by a 1989 hit comedy film of the same name, was supposed to premiere in September, but the series was put on hiatus after star Maura Tierney was diagnosed with breast cancer over the summer.

Tierney eventually dropped out of the show, and NBC had to recast her part, delaying the show till midseason. The nurse drama "Mercy" stepped in for "Parenthood" and has performed so-so, receiving a full-season pickup despite middling ratings.

Lauren Graham ("Gilmore Girls") took over Tierney's role.

"Parenthood" will take the place of "Heroes," whose future is very much in doubt after sinking to ratings lows this fall.

NBC's midseason schedule is below:

MONDAYS

8-9 p.m. - "Chuck" (begins Jan. 11; two back-to-back season premiere episodes on Jan. 10 from 9-11 p.m.)

9-10 p.m. - "Parenthood" (premieres March 1)

10-11 p.m. - "The Jay Leno Show"

TUESDAYS

8-10 p.m. - "The Biggest Loser" (new season premieres on Jan. 5)

10-11 p.m. - "The Jay Leno Show"

WEDNESDAYS

8-9 p.m. - "Mercy"

9-10 p.m. - "Law & Order: Special Victims Unit"

10-11 p.m. - "The Jay Leno Show"

THURSDAYS

8-8:30 p.m. - "Community"

8:30-9 p.m. - "Parks and Recreation"

9-9:30 p.m. - "The Office"

9:30-10 p.m. - "30 Rock"

10-11 p.m. - "The Jay Leno Show"

FRIDAYS

8-9 p.m. - "Law & Order"

9-10 p.m. - "Dateline NBC"

10-11 p.m. - "The Jay Leno Show"

SATURDAYS

8-11 p.m. - Encore Dramas

SUNDAYS

7-9 p.m. - "Dateline NBC" (through March 7, then moves to 7-8 p.m. beginning March 14)

8-9 p.m. - "The Marriage Ref" (debuts March 14)

9-11 p.m. - "The Celebrity Apprentice" (premieres Sunday, March 14)