There are still three Sundays left in the NFL regular season, but the shadow of the offseason is hovering for some teams and free agency is closer than it seems. That applies for players who are currently in the final year of their contracts, as the open market is within reach.
As we know, the open market can significantly impact a player's financial value. With multiple suitors comes the gift of leverage. Along those lines, let's take a look at the players who are soon to become free agents and might be worth more than you realize.

Mike Glennon, QB, Tampa Bay Buccaneers
The former second-round pick has 18 NFL starts to his name and should find himself in a comfortable situation this offseason. Tampa Bay has its franchise quarterback in Jameis Winston, so the price the Bucs are willing to pay Glennon likely has a ceiling. Meanwhile, the free-agent quarterback class looks weak (especially if, as expected, Kirk Cousins winds up back in Washington), and early evaluation of the 2017 draft class is that the QBs are just OK. Glennon has a 2:1 touchdown-to-interception ratio in his career and could be the most coveted open-market quarterback in a league where signal-callers are invaluable.

Terrelle Pryor, WR, Cleveland Browns
What a season it has been for the former quarterback, who has excelled in a full-time wide receiver role and set himself up for a major payday. Given Pryor's unique career arc, this is his first and best shot to cash in significantly. He's 27 years old and will likely surpass 1,000 receiving yards. While there are a lot of nuances to his game, a starting point is this: He looks like a natural-born receiver on the field. He's an outstanding athlete who can pluck the football in competitive catch situations and is very good after the catch. The Browns have endless cap space and may be inclined to use the franchise tag on linebacker Jamie Collins. Pryor should cash in.

Zach Brown, LB, Buffalo Bills
Brown isn't especially well-known. But he's a 27-year-old inside linebacker with 122 tackles, a pair of forced fumbles, an interception and a ton of good tape from 2016. He signed a one-year flier with the Bills this past offseason and was thrust into a leading role, in part because of a knee injury to rookie Reggie Ragland. Brown made good on his chance to play a heavy dose of snaps. He's reliable, covering ground at or near the line of scrimmage and also horizontally in space. The Bills may feel that Ragland and Preston Brown are the best starting duo at inside 'backer going forward, which would lead Zach Brown to the open market, where he figures to receive a handsome raise from his $1.25 million contract for 2016.

Tony Jefferson, S, Arizona Cardinals
The Cardinals face a critical offseason, when a slew of key players enter free agency. That list includes defensive end/outside linebacker Chandler Jones, defensive lineman Calais Campbell and Jefferson, a wildly underrated playmaking safety. He does a bit of everything as a terrific partner with Tyrann Mathieu in the Cardinals' safety crew. Jefferson is tough, can hold up in pass coverage (he snagged a pair of picks in 2015) and is a resource at or near the line of scrimmage, too. He has four sacks and more than 160 tackles since the start of 2015.

Ronald Leary, G, Dallas Cowboys
Dallas' offensive line is widely regarded as the best in football, and Leary's presence should not be overlooked. He took over as a starting guard when La'el Collins suffered an early-season foot injury, and the group hasn't been any worse off for it. A former undrafted free agent whose stock was impacted by a knee condition, Leary has pieced together essentially three full seasons as a starter. He's powerful at the point of attack and reliable both as a run- and pass-blocker. Teams are going to want to emulate Dallas' offensive blueprint, and I believe the guard position will be viewed favorably in free agency with the recent success of a player like Kelechi Osemele, who signed a major deal with Oakland last year.

Brandon Williams, DL, Baltimore Ravens
It's hard to quantify the value of a player like Williams, whose career stat line includes just 4.5 sacks in nearly four seasons. But don't let that fool you: He's an integral cog in what Baltimore does defensively and will be highly sought-after if he reaches the open market. He's a space-eating force who doesn't budge easily in the middle of a defense, enabling second-level defenders to fly to the ball. The Giants struck gold with the free-agent addition of Damon Harrison, and while Williams doesn't have the same production in the tackles department, he has a comparable role to Harrison's. Williams, 27, can anchor a defensive line.

Mario Addison, DE, Carolina Panthers
Addison has found his niche over the past three seasons, as he has racked up 20 sacks in 41 games played, none of them as a starter. He's a relentless rusher who can generate some burst off the edge. And although he's 29 years old, he offers a premium skill that is coveted on the open market. Robert Ayers, at the age of 30, parlayed a solid 2015 with the New York Giants into a three-year, $21 million deal from the Buccaneers in free agency. Don't be surprised if Addison earns a favorable deal in March.