ENGLEWOOD, Colo. -- The Denver Broncos enter 2021 NFL free agency coming off a 5-11 season in 2020 and have 15 unrestricted free agents, including many short-term signings this past season when a wave of injuries struck.

Safety Justin Simmons, who played on the franchise player tag this past season, and defensive end Shelby Harris lead the Broncos' list of players who are poised to hit the open market. The Broncos also have significant decisions to make on option years for linebacker Von Miller and safety Kareem Jackson.

Miller, one of the most decorated defensive players in franchise history, and Jackson have options in their current contracts that would engage the final year of each deal in 2021. If the Broncos don't engage those options, which kick in salary guarantees for the season, both players would be unrestricted free agents.

Here's what to expect from the Broncos when free agency opens March 17:

QUARTERBACK

Under contract: Drew Lock, Brett Rypien, Jeff Driskel

UFA: None

Game plan: There will be some change in this room even if Lock continues on a course through the offseason as the most likely starter. The Broncos could release Driskel, who signed a two-year deal last spring, with a limited dead money hit ($750,000). They'll be on the hunt for a veteran who can, at minimum, push Lock to repair his footwork and decision-making in what is shaping up to be a make-or-break year for him. The No. 9 overall pick in the 2021 NFL draft has the potential to yield a quarterback.

RUNNING BACK

Under contract: Melvin Gordon, Phillip Lindsay, Royce Freeman, Levante Bellamy

UFA: None

Game plan: Because of a DUI arrest last year, Gordon still faces the potential of a league suspension to open the 2021 season. He has a hearing for the DUI on March 10. The Broncos could also try to void some of the guaranteed money in his deal if he is suspended. Bottom line: His future has a question mark or two by it. Lindsay is a restricted free agent, so the Broncos can match any offers they receive. Overall, the Broncos just need more big-play pop from the position, especially in the passing game.

WIDE RECEIVER

Under contract: Jerry Jeudy, Courtland Sutton, KJ Hamler, DaeSean Hamilton, Tyrie Cleveland

UFA: None.

Game plan: Tim Patrick is a priority given he is a restricted free agent and an exceedingly high-value player other teams would certainly take a look at if the Broncos don't tender him with enough compensation. At $750,000 last season, Patrick was one of the best performance-over-pay players in the league, with 51 catches and six touchdowns. Otherwise this is a youthful, athletic group that should have Sutton back from a torn ACL to give any quarterback plenty to work with.

TIGHT END

Under contract: Noah Fant, Albert Okwuegbunam, Nick Vannett, Andrew Beck

RFA: Jake Butt

Game plan: The Broncos got just a glimpse of how Fant and Okwuegbunam could potentially challenge defenses when they're on the field together before Okwuegbunam suffered a torn ACL. Okwuegbunam's return from injury will be watched closely, but it's an important position in the Broncos' scheme and they'll take a look in both free agency and the draft for a little more help.

OFFENSIVE LINE

Under contract: Garett Bolles, Dalton Risner, Lloyd Cushenberry III, Graham Glasgow, Ja'Wuan James, Netane Muti

UFA: Demar Dotson, Elijah Wilkinson

Game plan: The Broncos have work to do with a wafer-thin depth chart along the offensive line. James has not played in two consecutive games in the same season since 2018 and will be returning from an opt-out year. George Paton's first draft class as the team's GM will need to include some of the big guys up front. Guard Austin Schlottmann is not under contract for 2021 but is an exclusive rights free agents, so he can only negotiate with the Broncos unless they release him.

DEFENSIVE LINE

Under contract: Mike Purcell, Dre'Mont Jones, McTelvin Agim, Isaiah Mack, DeShawn Williams

UFA: Shelby Harris, Sylvester Williams, DeMarcus Walker

Game plan: Jurrell Casey, who missed all but three games this past season, was released last week with no dead-money charges. He was scheduled to count $11.87 million against the cap. Harris would be a significant loss if he leaves in free agency, so this is another spot where the Broncos will keep an eye on the long list of productive veteran players who are expected to be salary cap casualties from other teams.

LINEBACKER

Under contract: Von Miller, Bradley Chubb, Josey Jewell, Malik Reed, Justin Strnad, Derrek Tuszka

UFA: Joe Jones, Anthony Chickillo, Jeremiah Attaochu

Game plan: Two rather enormous questions stare at the Broncos. First is whether or not they pick up the option in Miller's contract for the 2021 season. If they do, they'll be saying he's ready to have the kind of year they expected in 2020 before an ankle injury ended his season before it started. If they don't, well, that is a significant spot on the depth chart that will need filling, given they have chosen to move on from their longest-tenured and most decorated player. Second is Alexander Johnson, a restricted free agent. The Broncos can match any offers he receives, but unless they tender the compensation high enough to deter some of those offers, they can expect Johnson to draw some interest.

DEFENSIVE BACK

Under contract: Bryce Callahan, Michael Ojemudia, Kareem Jackson, Duke Dawson Jr., Essang Bassey, Parnell Motley, Nate Hairston, P.J. Locke

UFA: Justin Simmons, Will Parks, De'Vante Bausby, Alijah Holder

Game plan: Safety could go from a position of confidence to a position of great need in a heartbeat. Simmons, who played on the franchise player tag in 2020, would be one of the most coveted free agents in the open market. The Broncos also have a decision to make on picking up the option in Jackson's contract, and Parks is an unrestricted free agent. Cornerback also remains one of the Broncos' biggest need positions, overall, given they have already released A.J. Bouye and Callahan is coming off a second foot injury in the past two years.

SPECIAL TEAMS

Under contract: Brandon McManus, Sam Martin, Jacob Bobenmoyer

UFA: None

Game plan: Returner Diontae Spencer is not under contract, but he is an exclusive rights free agent and the Broncos have said they'd like him back. Otherwise, this is a stable position group, especially given Martin was just signed a year ago in free agency and McManus just signed his extension this past season.