The New York Times has lost Lydia Polgreen, editorial director of NYT Global, to Tim Armstrong’s AOL, where she will take over from Arianna Huffington as editor-in-chief of the Huffington Post.

The 66-year-old Huffington launched HuffPo in 2005 and then sold it to AOL for $315 million in 2011. She left in August to launch a new site, Thrive Global, which concentrates on health and wellness issues.

Polgreen may be tasked with dismantling the many lifestyle niche sites that Huffington had launched in recent years that lose money for HuffPo, sources said. The brand also aggressively expanded overseas, to mixed results, upping traffic but also draining cash.

And Polgreen’s job may only get harder when Verizon — which purchased AOL for $4.4 billion in 2015 — completes its $4.8 billion acquisition of Yahoo.

Armstrong said at a recent investment conference that he remains optimistic that the Yahoo deal will be completed — despite new ad woes at Yahoo and news of a massive security breach at the site.

Polgreen, in an interview with HuffPo, said it was “tough” to leave the Times after 15 years but that it was the “opportunity of a lifetime” to lead the Huffington Post.