Geri Wang, who has led advertising sales for ABC since early 2010, will step down from the role in March of 2017, the network announced Thursday, in an unexpected move that will see another veteran ad executive leave the TV industry. The announcement surprised several staffers in ABC’s ad-sales department, according to a person familiar with the situation.

Her departure will take place just as ABC and the nation’s other TV companies prepare for the industry’s annual “upfront” marketplace, when they try to sell the bulk of approximately $8 billion to $9 billion in advance ad commitments for the coming program season. The network said Wang had decided to retire after spending 27 years rising through the levels at the Disney-owned outlet. ABC did not name a successor in its announcement.

The announcement comes less than three months after Disney named Bruce Rosenblum as president of business operations of Disney/ABC TV. As part of his duties, the former Warner Brothers chief was granted oversight of ad sales at the unit’s properties, which include ABC, Disney XD and Freeform, among other outlets.

Wang is the latest in a growing line of senior ad-sales chiefs who are leaving the sector as the business of enlisting commercial support for TV programs moves through a period of massive flux. A growing digital audience means TV companies must also concern themselves with ways to connect advertisers to streaming-video and video on demand. More advertisers are focusing on so-called “programmatic” advertising that allows them to use software to find advertising inventory that best matches the audiences most likely to buy their products, and purchase that time more efficiently. Increasingly, these ad-sales veterans are grappling with the fact that a rising generation of viewers has, thanks to digital technology, become accustomed to not watching ads at all.

In recent months, Discovery Communications announced that Joseph Abruzzese, its head of ad sales, would leave the company at the end of the year. Toby Byrne, head of ad sales at Fox Networks, abruptly left his post after he and the company could not come to terms on a new contract. Arlene Manos, who has run ad sales at AMC Networks for years, in September said she would step back from many of her duties. Jeff Lucas, head of ad sales at Viacom, in June left that media conglomerate to take up a similar role at social-media company Snap Inc. Seth Winter, the longtime head of ad-sales efforts for NBCUniversal’s sports properties, has stepped away from many of his duties and now has a consulting role.

Wang has burnished a reputation as a no-nonsense salesperson focused on work at hand. In recent sales cycles, she has fought to maintain rate increases for ad time despite ratings fluctuations in ABC’s primetime schedule –  even if it meant depending more heavily on so-called scatter, or ad inventory that is not booked in advance.  She has had some ballast, such as  new series like “How to Get Away With Murder” and “Black-ish.” But at times she had had to contend with significant audience erosion, and the fact that ABC relies less on pricey primetime sports than its competitors.

“While we all understand and respect Geri’s decision, she will be greatly missed – both inside Disney|ABC and around the globe with our many clients,’ said Ben Sherwood, co-chairman, Disney Media Networks and president, Disney|ABC Television Group,in a prepared statement. “Geri is a force of nature – one of the best and brightest in our business. Relentless in her commitment to ABC, formidable at the negotiating table and a fierce advocate for all clients, she has raised the standards of everyone who works with her.”

If ABC favors an internal candidate, it could pick among several. Debbie Richman, ABC’s senior vice president of primetime ad sales, is a former top TV buyer with Omnicom Group’s OMD, and the force behind some of ABC’s biggest properties, like its annual Oscars broadcast. Rita Ferro, executive vice president of sales for Disney’s various kids networks, is expert in the ways of marketing to younger viewers. Laura Nathanson, executive vice president of national ad sales at Disney’s Freeform cable network, has in recent seasons worked with interesting multi-screen efforts.

Wang is married to Mike Shaw, who was ABC’s ad-sales president before she took over the role. Shaw retired in late 2009, and has been known to enjoy travel in his retirement. Wang may want to visit frontiers beyond the Magic Kingdom.

[Updated, 4:31 PM PT]