AceShowbiz -

The date for the premiere of long-delayed "Parenthood" has been announced when NBC unveils its 2010 midseason schedule. The drama that originally was Maura Tierney's starring vehicle skipped the Fall season to debut on Monday, March 1 being led by "Chuck".

Tierney had to undergo a medical treatment and was unable to continue her commitment to the show. She was eventually replaced by Lauren Graham. This midseason, the series premieres just right after "Heroes" wraps up its season finale on February 8 and NBC finishes its Winter Olympics cover on February 28.

As previously reported, the almost-canceled "Chuck" will begin the third season on Sunday, January 10 with a two back-to-back episode starting 9/8c. It will move to the regular slot on Mondays beginning January 11 at 8/7c.

At the same time, NBC announced that this season's "The Biggest Loser" would be another "Couples" edition. Comprised of 11 pairs, the competition will begin on January 5. Meanwhile, Jerry Seinfeld's new comedy "The Marriage Ref" is put on Sundays 8/7c with the premiere on March 14. The new season of "The Celebrity Apprentice" kicks off the same day.

MONDAYS

8-9 P.M. - "Chuck" 9-10 P.M. - "Parenthood" 10-11 P.M. - "The Jay Leno Show"

TUESDAYS

8-10 P.M. - "The Biggest Loser" 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. - encores of dramas

SUNDAYS

7-9 P.M. - "Dateline NBC" 8-9 P.M. - "The Marriage Ref" 9-11 P.M. - "The Celebrity Apprentice"