The two sides have exchanged multiple proposals within the past few days, NFL Media's Rand Getlin reported, via a source with knowledge of the discussions.
NFL Media's Mike Garafolo reported on Friday that Miller rejected the Broncos' latest proposal. The two sides are expected to continue negotiations through the weekend.
"They moved up the date for some of that non-guaranteed money, non-fully guaranteed money at signing to become fully guaranteed," Garafolo said on Friday's edition of NFL Total Access. "But that sweetening of the pot is not sweet enough for Von Miller."
In an interview with ESPN on Saturday, Miller reiterated that he will not play on the franchise tag and that money isn't a motivating factor for him.
"Never really played for money, hard to get me to do stuff, but it's bigger than one year," Miller said. "It's a leaguewide problem that I feel like I'm in a situation I can help out with.
"...Came into the league trying to help people out who played before me and after me, but at the end of the day, it's my contract with the Denver Broncos," he continued. "It's bigger than me, bigger than this -- issue is leaguewide, NFL vs. other pro sports. Huge difference."
The primary source of contention, per Getlin, continues to be the structure of the guaranteed portion of the contract and the payout over the first two to three years.
A new deal for Miller has been complicated, the source told Getlin, by the recent mega contracts signed by Eagles defensive tackle Fletcher Cox and Colts quarterback Andrew Luck. Cox landed $63.3 million in guarantees with $36.3 million up-front, while Luck reeled in $44 million at the signing with $87 million in guarantees.
If Miller doesn't sign by July 15, his options are to hold out or play the 2016 season on the $14.129 million franchise tag.