With free agency approaching (March 9), we're analyzing the biggest needs on the New York Jets' roster, examining possible upgrades:

Position: Defensive line

2017 cap hits of top returnees:

Pending free agents: Mike Pennel (restricted).

Key stat: The defense was terrible with a four-man rush. It allowed 19 touchdown passes, made only three interceptions and surrendered a league-high 109.5 passer rating, according to ESPN Stats & Information. Leaky coverage in the secondary was partly responsible, but the big fellas up front have to take a big share of the blame.

The Jets will probably ask for a first-round pick for Sheldon Richardson but will likely have to settle for less. Kelley L Cox/USA TODAY Sports

Money matters: The Jets have a ridiculous amount of money invested in the line, especially when you consider they play a 3-4 base front. Wilkerson, Richardson and Williams are counting a combined $31.2 million on the cap. It means close to 20 percent of the team's resources is devoted to three players who play basically the same position. By the way, Richardson's salary (the amount of his fifth-year option) becomes fully guaranteed on March 9. Wilkerson's entire base salary for 2017 ($14.75 million) is guaranteed, so forget about a trade. No team would take on that contract.

Big picture: The spotlight will be on Richardson for the next few weeks, as the Jets almost certainly will try to trade him. They can deal him now and get something in return or lose him next year for nothing (unless you count a compensatory pick in 2019). The Jets will ask for a first-round pick for Richardson, but they will have to settle for less, perhaps a third-rounder. He's a talented player, but he spent last season acting as if he wants out. There's also the scheme issue. If they won't play him in his natural position (3-technique), they might as well use him as a bargaining chip. It's laughable to use him at outside linebacker. Williams and Wilkerson are two solid anchors at end, with McLendon and Deon Simon in the middle.

Free-agent market watch: Brandon Williams (DT), Kawann Short (DT), Calais Campbell (DE), Jason Pierre-Paul (DE), Sylvester Williams (DT), Bennie Logan (DT), Dontari Poe (DT), Chris Baker (DT), Domata Peko (DT), Alan Branch (DT), Frostee Rucker (DT), Charles Johnson (DE), Mario Williams (DE), Jared Odrick (DT).

Also could become available: Arthur Jones (DT), Michael Johnson (DE), Haloti Ngata (DT), Tyson Jackson (DT).

The game plan: Two words: Stand pat. The Jets don't have to spend any money; they have a good mix of young and middle-aged players. They will be fine if Wilkerson returns healthy and motivated and Williams continues to develop.