Optimism remains, but the reality of a deadline has intervened. The Broncos have been encouraged by contract talks with Von Miller, but barring a last-minute agreement, they are expected to place the exclusive franchise tag on their all-pro outside linebacker before Tuesday’s deadline arrives.

Negotiations gained momentum last week at the NFL scouting combine, where general manager John Elway met with Miller’s agent. The franchise tag represents a tool for the Broncos to buy time to strike a long-term deal before July 15. The tag would guarantee Miller a salary of $14.04 million for the 2016 season if a long-term deal isn’t secured.

The Broncos’ three previous franchise-tag players all agreed to long-term contracts: offensive tackle Ryan Clady, kicker Matt Prater and wide receiver Demaryius Thomas.

WATCH: How will the Denver Broncos use the franchise tag?

An exclusive tag represents a difference from Thomas last season, and signals in the strongest terms that Miller isn’t going anywhere. Under this designation, Miller would not be permitted to negotiate with other teams. His salary would be calculated by the average of the five highest 2016 salary cap numbers at his position.

The nonexclusive tag was applied to Thomas last year. That permitted teams to sign Thomas to an offer sheet that the Broncos could match, and if they refused, they would receive two first-round draft picks.

Justin Houston’s six-year, $101 million contract with the Kansas City Chiefs is note- worthy in Miller’s situation. Houston, an outside linebacker, received a $20.5 million signing bonus last July in a deal with $52.5 million guaranteed. CBS Sports’ Joel Corry, a former agent, predicted last week that a Miller deal would average at least $17 million per season with $55 million guaranteed.

The tone in talks with Miller has been amicable because both parties are motivated. Miller wants “peaceful” negotiations, and the Broncos want him as part of their future core after he wrote a diary of destruction in the playoffs, collecting five sacks and Super Bowl 50 most valuable player honors.

Denver also is trying to keep defensive end Malik Jackson in the fold before free agency opens March 7. Jackson is believed to want $14 million per season, leaving him poised to test the market. The Broncos have offered less than $11 million thus far, trying to find common ground with the University of Tennessee alum.

In his fourth NFL season, Jackson provided run support, delivered five sacks and caused havoc with seven passes defended. He capped his 2015 season with a touchdown in Super Bowl 50, pouncing on a fumble created by Miller’s strip sack of Carolina Panthers quarterback Cam Newton.

Troy E. Renck: trenck@denverpost.com or @troyrenck