"It's a graceful way to go. It's the end of my contract this year, and the story line has been so perfect," the 57-year-old actress told Entertainment Weekly, which first reported the news. "I've given it my best for 16 years. It's time to move on. I'm doing other things and this will be a great way to leave what has been an extraordinary gig."
Merkerson, whose character was diagnosed with cancer earlier this season, says she doesn't know yet if Lt. Van Buren will live or die. "Van Buren is a hell of a character. However they decide to take her out, it'll be worthy of the character," she told EW. "Either way, it'll be great for me because I get to act it."
Although the fate of Law & Order — now in Season 20 — is also in question, the longtime cast member has faith it will return. "They say that every other year and the show always comes back," she told EW of the series, which is poised to break Gunsmoke's record for longest-running prime-time drama if it is renewed. "It's a great show. It's well-written. It has great integrity. It has a huge following."
Merkerson, who won an Emmy, Golden Globe and Screen Actors Guild awards for her performance in the 2005 HBO film Lackawanna Blues, said she's next producing and directing a documentary.
"It's exciting for me to be able to learn new things, she said. "I'm sure it will be emotional, but right now I'm just really happy for having had the opportunity."
NBC refused to comment on Merkerson's departure.