(UNDATED) - The Big Ten is close to finalizing a new media rights agreement that will add CBS and NBC to the league's lineup while ending a long partnership with ESPN, according to sources. Fox will remain the Big Ten's main media partner and had representatives attend negotiations with other potential partners during the past few months. The Big Ten's six-year media rights deal with Fox and ESPN is set to expire in 2023. ESPN and the Big Ten have been partners for football media rights since the early 1980s. ABC, which, like ESPN, is owned by parent company Disney, first started televising Big Ten games in 1966. Sports Business Journal first reported the outline of the Big Ten's media agreement and ESPN being out. According to sources, ESPN rejected the Big Ten's final offer of a seven-year, $380 million agreement, which would have included rights to fewer marquee games than the network's current agreement. The offer did not include a direct-to-consumer package, which ESPN valued through its growth of ESPN+. The Big Ten's new agreement likely will feature CBS broadcasting football games in a mid afternoon time slot, which had previously been filled by SEC games. Beginning in 2024, ESPN will exclusively broadcast SEC games as part of a 10-year agreement. NBC, which carries Notre Dame home football games, likely will have Big Ten football in the evening window as part of the new agreement. Sports Business Journal reported that both CBS and NBC are set to pay about $350 million for their Big Ten packages. Big Ten commissioner Kevin Warren said July 26 at football media days that he looked forward to welcoming new media partners into the league. The Big Ten's new media rights agreement, which still must be approved by league presidents and chancellors, reportedly is set to bring the league more than $1 billion annually.