There's a "Nashville" plot change on the horizon. As Hayden Panettiere receives treatment for postpartum depression, the main question left unanswered is what will happen to Panettiere's character, Juliette Barnes, on the ABC country musical drama.

A source connected with "Nashville" told The Hollywood Reporter the show revealed that production of the series will be "adapting" following the actress' decision to enter a treatment facility. Panettiere will temporarily step away from her role on the show and the production will work around her, according to Page Six.

Panettiere is one of the two main stars on the show alongside Connie Britton.

"They need to regroup and change storylines," a source reported the New York Daily News. "They will need to rewrite the plot since it's undetermined how long Hayden will be gone."

At the end of season three, Panettiere's character was seen throwing a snow globe at her estranged husband Avery Barkley, played by Jonathan Jackson, and their baby Cadence. In season four, the country star was seen partying without her husband or daughter. A source told People that Panettiere's storyline was "planned and started playing out long before and the groundwork for the postpartum storyline began way back last season [before Hayden gave birth]."

On Tuesday, Panettiere, who had her first baby, Kaya, in December with boxer and fiancé Wladimir Klitschko, voluntarily entered a treatment center for postpartum depression.

During her visit to "Live! with Kelly and Michael" last month, Panettiere opened up about her struggle with depression after giving birth to her daughter.

"It's something a lot of women experience," she told hosts Kelly Ripa and Michael Strahan. "When [you are told] about postpartum depression you think it's 'I feel negative feeling towards my child; I want to injure or hurt my child.' I've never, ever had those feelings. Some women do. But you don't realize how broad of a spectrum you can really experience that on. It's something that needs to be talked about. Women need to know that they're not alone, and that it does heal."

"Nashville" airs on Wednesdays at 10 p.m. EDT on ABC.