AP/Charles Dharapak
Greta Van Susteren in Washington in 2013.
MSNBC anchor Greta Van Susteren announced in a tweet that she is leaving the network after just six months."I am out at MSNBC," she wrote.
Van Susteren's new show premiered in January, several months after she was taken off the air at Fox, where she had worked for over a decade, amid a difficult contract renegotiation.
Chief legal correspondent Ari Melber, who has played a number of different roles at the network over the past several years, will replace Van Susteren permanently.
MSNBC President Phil Griffin informed staff about the change in a memo Thursday afternoon.
"MSNBC and Greta Van Susteren have decided to part ways," Griffin wrote. "Greta is a well-regarded television veteran and one of only a few broadcasters who can say they've hosted shows at all three major cable news networks. We are grateful to her and wish her the best.
"I'm also pleased to share that Ari Melber, MSNBC's Chief Legal Correspondent and host of the 'The Point' on weekends will become the permanent host of the 6pm hour next month. Ari is a frequent presence on TODAY and across various MSNBC shows and will continue those appearances as he takes on his new duties."
While cable programs often take years to steadily grow ratings, Van Susteren's show at 6 p.m. was one of the lower-rated shows on cable news in her time slot.
In the second quarter of this year, she trailed both Bret Baier's "Special Report" on Fox and Wolf Blitzer's "Situation Room" on CNN in overall viewers and in advertisers' coveted demographic of viewers between 25-54 years-old.