Germany's football association is expected to announce terms of the rights auction next week for the four seasons from 2017/18 to 2020/21. Sky Deutschland paid 2.5 billion euros (£2 billion) in 2012 to secure all the current live rights, including online.
The terms of the auction, which have to be approved by the German cartel office, have changed more than once in the past weeks and could change again, one of the people cautioned. "It's a work in progress," the person said.
The cartel office said it expected to approve the terms shortly but would not comment on what they would be. The German football association declined comment.
The Bundesliga is a key attraction for viewers of Sky Deutschland, which competes with dozens of free-to-air and cable channels in Germany and increasingly with Internet services such as Netflix, so-called over-the-top (OTT) players.
If Sky or another bidder were to win all the live rights, a package of around 90-100 games would be clawed back to sell to an OTT player, the sources said, confirming a report to be published in German magazine Spiegel.
UK-based digital sports content and media company Perform Group, which won rights at the end of last year to show English Premier League games in Germany, is expected to show interest in the online Bundesliga rights.
German public broadcasters ARD and ZDF currently have rights to show Bundesliga highlights and a few key live games. Free-to-air broadcaster ProSiebenSat.1 also has a package of broadcast rights but not for live games.
(Writing by Georgina Prodhan; Editing by Maria Sheahan)