The unit of Fox that for more than a decade has sold the national inventory for all the nation’s major RSNs — including soon-to-be owner Sinclair — is a favorite not only of RSNs, but also of sports-minded media agencies because it’s a one-stop shop, allowing them to easily buy major professional and college on a national basis.

AT&T Inc. is weighing a sale of its regional sports networks as part of a plan to cut as much as $8 billion in debt by the end of the year, according to people familiar with the matter. Sinclair Broadcast Group, which agreed in May to buy 21 Fox regional sports networks from Disney for $9.6 billion, could be among the potential buyers, the people said.

A trio of Democratic Senators/presidential candidates — Elizabeth Warren, Cory Booker and Bernie Sanders — has asked both the FCC and Justice Department to take a hard look at Sinclair’s purchase of Disney’s (formerly Fox’s) 21 regional sports networks (RSNs), saying they are worried both about Sinclaircombining the RSNs with its TV stations to raise the price of carriage for the latter, and about the “danger” of Sinclair’s “partisan political” programming getting a wider audience.