According to the Article the contract for WFAN to air Nets games goes up to 2020-2021 NBA Season

Entercom and the Brooklyn Nets have reached a new multi-year agreement that extends the team's broadcast rights with WFAN/New York through the 2020-21 season. The rights include airing regular season and any postseason games. In addition, WFAN will continue to be the home of the Nets pre- and post-game coverage for all contests broadcast on the station. Co-owed WCBS (Newsradio 880), the team's ancillary broadcast outlet, will provide game coverage of select matchups.

"We're proud to continue to be the radio home of the Nets," said Regional President/Market Manager Susan Larkin. "We remain committed to bringing our listeners and partners the most exciting sports content from their hometown teams."