"Parenthood" star Maura Tierney

"Parenthood" star Maura Tierney

An eight-week medical evaluation for actress Maura Tierney has caused the premiere of NBC’s new fall drama “Parenthood” to be moved to a midseason. A video preview of the show is below.

The show was a key component for NBC’s Wednesday night fall lineup, but now production on new show “Mercy” has been kicked into high gear so that it can premiere in September instead. While there are no details as to what condition requires an eight-week medical evaluation for Tierney, the network has released a statement asking everyone to respect her privacy at this difficult time.

“Parenthood” is based on the 1989 movie starring Steve Martin, Rick Moranis, Jason Robards, Tom Hulce, Dianne Weist and Mary Steenburgen. Tierney plays the character that Weist played in the movie, a single mother with two teenaged children. Her costars include Peter Krause, Erika Christensen, Dax Shephard and Craig T. Nelson.

The replacement show, “Mercy,” is a hospital-based show starring Michelle Trachtenburg, Delroy Lindo, Guillermo Diaz and James LeGros.

“Parenthood” preview video: