The NFL is embarking on an offseason that could change the shape of numerous franchises.

While the league has yet to set the precise salary cap for the 2021 season, it is expected to be around $180 million. Teams can't engage in discussions with free agents until March 15 and are prohibited from signing them until two days later, but that doesn't mean franchises and players aren't aware of what's looming.

In free agency, a good addition such as when the Colts signed quarterback Philip Rivers, can turn a team coming off a losing season into a playoff contender. Conversely, a poor choice can stunt a team's growth — for example, the one-year, $20 million deal Arizona gave to oft-injured quarterback Sam Bradford in 2018.

Free agent decisions create a ripple effect throughout the league, with teams left to fill voids and free agents getting a gauge of what their market value is with other signings in their position groups. Franchise and transition tags can also be used on pending free agents between Feb. 23 and March 9 and can shape the free agent market.

Here are five free-agent situations that will shape the offseason:

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1. QB Dak Prescott, Dallas Cowboys: The Cowboys and their franchise signal-caller have been working on a long-term deal for the past couple years without success. Now, it has likely come to a head.

Before Prescott suffered a compound fracture and dislocation of his right ankle in a win over the New York Giants on Oct. 11, he had thrown for 10,643 yards, 61 touchdowns and 23 interceptions, in addition to rushing for 12 scores, in his previous 37 games.

Prescott, who turns 28 in July, played under a franchise tag this past season. If he has to be franchise-tagged again, he'll make more than $37 million in 2021, which could prevent the Cowboys from adding pieces to their defense, which struggled mightily at times last year.

The Cowboys are among roughly a dozen teams with the quarterback position in flux. Prescott is the headliner of this year's potential free-agent quarterback class, with a steep drop-off to Chicago's Mitchell Trubisky, Miami's Ryan Fitzpatrick and New England's Cam Newton.

2. RB Aaron Jones, Green Bay: Jones bet on himself this year. The Packers reportedly offered him a contract before last season that would have made him among the five highest-paid players in the league. But he turned it down because he was unhappy with the deal's guaranteed money.

Jones was terrific for the second straight season. He made his first Pro Bowl with a career-high 1,104 rushing yards and nine touchdowns in two fewer games and 35 fewer carries than in 2019. Jones also caught 47 passes for 355 yards and two touchdowns, continuing to be a valuable check-down target for Aaron Rodgers.

How Green Bay handles Jones, who signed a four-year, $2.601 million deal as a rookie, likely sends a message to Rodgers regarding the team's offensive philosophy. Jones' backup, Jamaal Williams, is also a pending free agent, and it's unlikely both return with 2020 second-round pick AJ Dillon also on the roster.

Jones' situation will impact a free-agent group of running backs that includes Arizona's Kenyan Drake (955 yards, 10 TDs), Seattle's Chris Carson (681 yards, 5 TDs), Tampa Bay's Leonard Fournette (367 yards, 6 TDs) and Atlanta's Todd Gurley (678, 9 TDs).

3. Which receiver signs first?

The top tier of free-agent receivers is deep. Chicago's Allen Robinson II, Tampa Bay's Chris Godwin, Detroit's Kenny Golladay and Pittsburgh's JuJu Smith-Schuster could all hit the market and would command top dollar. But how much?

That's the biggest question because the receiver who signs first — whether it is with his team or another franchise — could set the market for the others.

Robinson has 200 receptions for nearly 2,400 yards to go along with 13 touchdowns the past two seasons catching passes from Trubisky, Nick Foles and Chase Daniel. Robinson, who turns 28 in August, is also coming off a contract that paid him $42 million over three seasons, with more than $25 million guaranteed.

Godwin, who turns 25 later this month, has 151 catches for nearly 2,100 yards and 16 touchdowns during the same time span. He also had the luxury of playing with Tom Brady this season and alongside premier receiver Mike Evans during his time in Tampa. He's in line for a huge raise after completing his four-year, $3.284 million contract rookie contract.

Golladay established himself as a go-to receiver with a combined 135 receptions for 2,253 yards and 16 touchdowns from 2018-19. However, he was limited to just 20 catches in five games in 2020 due to a nagging hip injury.

Will a team pay top dollar to the 27-year-old Golladay, who is coming off a four-year, $3.196 million deal?

Smith-Schuster caught 97 passes for 831 yards and a career-high nine touchdowns in 2020 and doesn't turn 25 until November. He could also be expendable to the Steelers, who are deep at receiver with Chase Claypool, Diontae Johnson and James Washington.

Smith-Schuster will be looking for a much bigger payday now that his four-year, $4.195 million rookie contract is over.

The next tier of receivers includes Tennessee's Corey Davis, Houston's Will Fuller V, Carolina's Curtis Samuel and Tampa Bay's Antonio Brown.

4. What will the Ravens do with DEs Matthew Judon and Yannick Ngakoue?

The Ravens will likely be in the market for one of the above wide receivers to improve a league-worst passing offense (171.2 yards per game in 2020). They also have a major decision to make regarding their premier edge rushers.

Judon, a two-time Pro Bowler who recorded 6.0 sacks this season after recording 9.5 in 2019, played under a $16.808 million franchise tag and could command $20 million annually in his next deal.

So too could the 25-year-old Ngakoue, who the Ravens acquired in an in-season trade with Vikings. He had 8.0 sacks and four forced fumbles combined between the two teams while earning $12 million in 2020.

The free-agent class of edge rushers is fairly deep. It includes Denver's Von Miller, Tampa Bay's Shaq Barrett, Pittsburgh's Bud Dupree, Washington's Ryan Kerrigan, San Francisco's Kerry Hyder, the Los Angeles Chargers' Melvin Ingram and Tennessee's Jadeveon Clowney.

5. What's LT Trent Williams' future in San Francisco?

It's not often a premier left tackle hits the open market, but that could be the case with Williams, an eight-time Pro Bowler who returned to dominating form in 2020 after sitting out all of 2019 due to a contract dispute with Washington.

San Francisco gave Washington two draft picks to acquire Williams, but the 49ers will have to give the 6-foot-5, 320-pounder a new contract to keep him. Williams, who turns 33 in July and is coming off a five-year, $68 million deal, is in line for the biggest payday of his career.

If Williams leaves San Francisco, the 49ers could still find a good — but not great — replacement in free agency. Pittsburgh's Alejandro Villanueva, Philadelphia's Jason Peters, Jacksonville's Cam Robinson and Carolina's Taylor Moton and Russell Okung headline a deep class.