FOXBOROUGH, Mass. -- March brings the start of free agency that much closer. Teams can negotiate with player agents for unrestricted free agents from other teams starting March 12, with free agency officially starting on March 14.

Meanwhile, teams can negotiate extensions with their own free agents at any point up until that time, which highlights the importance of understanding the financial market at various positions.

With this in mind, after looking closer at a potential market for left tackle Nate Solder, and also free-agent-to-be running back Dion Lewis, let's move forward to cornerback Malcolm Butler.

Cornerback Malcolm Butler, who is heading toward free agency, has shown the durability that teams covet, having played in at least 96.7 percent of the Patriots' defensive snaps in each of the past three regular seasons. Gregory Payan/AP Images

Hitting the market at 28: From an experience and age standpoint, Butler is in the sweet spot that most teams would find desirable: He just turned 28 this past Friday and he's played in 97.8, 96.7 and 98.8 percent of the defensive snaps in each of the past three regular seasons. One of his best assets is his competitiveness, although 2017 was an inconsistent season for him. Still, given that teams can never have enough corners, Butler should have a market for his services as the expectation after Super Bowl LII is that he and the New England Patriots will part ways. He was a Pro Bowler in 2015 when the Patriots viewed him capable of being the top option to replace departed No. 1 cornerback Darrelle Revis.

Market watch: The Patriots' five-year, $65 million deal for unrestricted free agent Stephon Gilmore last offseason was a strong deal near the top of the market because it included $31 million in guarantees. Josh Norman's five-year, $75 million pact, with $36.5 million in guarantees, was signed in 2016 and still holds up well. It's highly unlikely Butler will be in that neighborhood, but after making $3.9 million as a restricted free agent in 2017, he should be in line for a significant bump. Jets cornerback Buster Skrine, who signed a four-year, $25 million deal ($13 million in guarantees) as an unrestricted free agent in 2015, is one player who could be viewed as comparable to Butler in terms of physical makeup and playing experience when hitting the market. More recently, Logan Ryan's three-year, $30 million pact with the Titans as an unrestricted free agent in 2017 might be more timely from an analysis perspective. Robert Alford's four-year, $38 million extension with the Falcons in 2016 is in a similar financial neighborhood.

Patriots' cost replacement analysis: As director of player personnel Nick Caserio recently explained at the MIT Sloan Sports Analytics Conference, when it comes to a free agent, "There is a cost component that certainly comes into play relative to their role and relative to the replacement cost or replacement player behind them." In this case, after Super Bowl LII, the feeling here is that it would take a Hail Mary for Butler to return to the Patriots at any cost. The team has Gilmore locked in at one spot, with Eric Rowe ($1.1 million), Jonathan Jones ($630,000) and Cyrus Jones ($814,246) next on the depth chart. A draft pick could also be part of the consideration. Given the Patriots' other needs on the roster, and other free-agent priorities (e.g. Solder), paying a second cornerback at mid-to-high levels seems highly unlikely. One could say, whether agreeing with it or not, the passing of the torch to Rowe at that spot already happened in Super Bowl LII.

Final analysis: Butler's market will be fascinating to watch unfold because it doesn't seem as clear-cut as someone like Solder's, and also to see if coach Bill Belichick's decision not to play him in Super Bowl LII has any impact on teams' pursuit. Butler, coming off an inconsistent season, has earned whatever he has coming to him. One of the oft-repeated sayings in New England is that durability can be as important as ability, and with that in mind, Butler should be appealing to corner-needy teams who have a financial structure that can absorb a corner anywhere between the $6 million-per-year-and-up range (Logan Ryan's $10 million per year).