Mercy Date: NBC Books Fast-Tracked Drama for Wednesdays

NBC has announced a Sept. 23 premiere for Mercy, the new medical drama that had its debut suddenly moved from midseason to fall.

The series will airs Wednesdays at 8 pm/ET, where its competition is ABC's Hank and The Middle, CBS' Old Christine and Gary Unmarried, Fox's So You Think You Can Dance, and the CW's Top Model.

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Mercy cast and crew were notified late last week that they must report to work in August versus October, now that the show is needed to fill a gap created by a delay in the start of production for Parenthood.

An adaptation of the 1989 movie, Parenthood had its premiere pushed back to midseason to allow time for star Maura Tierney to have and recover from surgery to remove a tumor in her breast.

Tierney, calling hers "a very treatable condition," said in a statement, "I'm very optimistic as to the outcome... I look forward to going back to work soon."

Mercy stars Michelle Trachtenberg (Gossip Girl), Taylor Schilling (Dark Matter) and Jaime Lee Kirchner (Rescue Me) as nurses. The cast also includes James Tupper (Men in Trees), Diego Klattenhoff (Supernatural) and Guillermo Diaz (Weeds).

Despite Mercy's fast-tracked production start, Trachtenberg is still expected to appear in several episodes of Gossip Girl's new season, as troublemaker Georgina Sparks.