Walsh has played Dr. Addison Montgomery for seven years -- the character spun off from "Grey's Anatomy" and then left Seattle Grace for her own practice in L.A. Deadline reports that Walsh's deal was up at the end of Season 5, but she agreed to sign on for 13 more episodes. According to the website, she will exit after those episodes are up.
"Private Practice" saw another shocking departure earlier this week when series star Tim Daly, who played Dr. Pete Wilder on the show, tweeted that he was leaving the show and would not be part of Season 6. Daly had been with the series since its debut in 2007.
Walsh responded to Daly's news via Twitter with well wishes.
"Private Practice" returns with new episodes this fall on Tuesdays, 10 p.m. ET on ABC.
Find out which other shows will be back by clicking through the slideshow below.