NBC is flip-flopping a fall series and a midseason series due to an actress fallling ill. According to The Hollywood Reporter, the network is moving its new series Parenthood to a midseason premiere.

The move is due to Parenthood star Maura Tierney's undisclosed medical ailment. While the studio wouldn't disclose more information, they released the following statement:

"The top priority for NBC, Universal Media Studios and Imagine Television is the well-being of Ms. Tierney. We are unable to release further details and ask that you respect her privacy at this time."

Parenthood was slotted for a September 23 premiere and was scheduled to air on Wednesday nights at 8 PM ET, and now the network is calling up one of its midseason series' early.

Mercy will now premiere in the fall, although it wasn't clear whether it would take Parenthood's exact slot, as they're reevaluating their fall lineup. Mercy cast and crew members have been called into production early to get the show ready for a fall premiere.