It's no secret that the Philadelphia Eagles need to revamp/retool/rebuild/reassemble their lackluster defensive group.

While acknowledging the obvious caveat of being forced to play opposite Chip Kelly's up-tempo, breakneck offense and the immensely inflating effect it has on time of possession and the defense's number of plays faced and overall yardage and points surrendered, it remained a not very clutch/quality/capable/good group by the end of this season.

Beyond a very strong defensive line, led by Pro Bowl snub, defensive end Fletcher Cox, ascending nose tackle Bennie Logan and the dependable run stopper but still improving pass rusher, Cedric Thornton, the Philly defense - which surrendered just the 15th most rushing yards in the league per game, but also finished 31st in passing yards - continues to be a work in progress.

While head coach Chip Kelly, recently anointed personnel czar and Grand Organizational Poobah by team owner Jeffrey Lurie, would no doubt prefer to build through the draft, there are always a handful of spots that require immediate upgrade and thus players the team must add through free agency or trade.

The defensive backfield for the Eagles is, to put it bluntly, a mess. And the linebacking corps, even with the continued growth of the explosive Mychal Kendricks, the expected return of aging field general DeMeco Ryans and the consistently strong play of outside linebacker Connor Barwin, is questionable at best.

For the secondary, starting cornerback Bradley Fletcher is a free agent and almost assuredly gone. Nate Allen is facing the same fate. Cary Williams is still under contract but his cap figure jumps dramatically - $8.16 million, with only $1.6 million in dead money were the team to cut him - and he may be upgraded if at all possible. Veteran backup Nolan Carroll found a role as a quasi-linebacker in the dime package this year and could take over Fletcher's spot for next season, but it isn't a certainty. Nickelback Brandon Boykin and rookie Jaylen Watkins will return, but it is difficult to say whether or not their roles will change or, more importantly, increase.

In short, safety Malcolm Jenkins may be the only returning starter in the secondary for the Eagles and defensive coordinator Billy Davis next season.

As for the linebackers, Kendricks and Ryans will likely the man the two starting inside spots and the first-time Pro-Bowler Barwin will take one of the two outside spots in Davis' 3-4 base. Quarterback hunter and Philly fan favorite Trent Cole will, barring a contract restructuring - he's slated to make $11.625 million next season - find himself playing elsewhere for the first time in his career.

Graham finished this season with 46 tackles, 5.5 sacks and four forced fumbles, playing his way into contract extension talks with the team, but may be more comfortable - and make more money - elsewhere as an end in a 4-3. There's no question he'll at least test the free agent waters and, considering some of the inflated contracts given to pass rushers, could very easily price himself out of Philly.

Last April's first-round draft pick, Marcus Smith II, has shown nothing of note thus far. He bounced around between inside and outside linebacker his rookie season, which the team admitted may have stunted his growth, at least in the short term, but while it's far too early to label him a bust, it's also impossible to count on his contribution.

Now, free agency is less of a crapshoot than the draft - players have an NFL track record of proven success or failure so you're operating with a much clearer idea of what you're getting - but it certainly shouldn't be leaned upon as a way to build a winning franchise.

It's been proven time and again that that approach simply doesn't work - Dream Team represent!

But, like last season when the team signed Jenkins and Carroll and special teams mavens Chris Maragos and Bryan Braman, or the year before when they brought in Connor Barwin and James Casey, there are always a couple spots you can get away with buying your way to new and, if the free agent evaluation process is a successful one, ascending contributors.

So, what pending free agents around the league could Kelly look to add as he attempts to inject some talent and vitality into the floundering/flagging/frustrating/feckless Philly defense?

How about New York Giants defensive end Jason Pierre-Paul?

The first thing you've got to talk about when connecting JPP and the Eagles, is health. Kelly has stated in the past - in reference to quarterbacks but it's probably not a stretch to assume that it could apply to all positions in the lineup - that "the best ability is durability."

JPP, who had an absolute monster of a season in 2011, his second in the league, when he busted out for 16.5 sacks and helped the Giants to their fourth Super Bowl championship, has since stumbled his way through a couple of injury marred campaigns that limited his overall effectiveness and ability.

JPP played in all 16 games in 2012, but a combination of reported back injuries and the oppositions increased focus on limiting his impact left him with just 6.5 sacks and 66 tackles. 2013 saw him dress for only 11 games and manage a putrid 2.0 sacks and 20 tackles.

This past season - I know, I know, in a contract year, always questionable - JPP appeared to have nearly regained his 2012 form, finishing the regular season with 77 tackles and 12.5 sacks on a horrid Giants defense that finished 30th in yards allowed and got their defensive coordinator fired.

He's got the size (6-foot-5, 278-pounds) and length (34-3/4-inch arm length, 10-3/8-inch hands) that Kelly covets - remember, big people beat up little people - and he's certainly got good enough athleticism to thrive as a 3-4 outside linebacker - 4.71 40-yard dash, 4.67 short shuttle, 7.18 3-cone - both rushing the passer and dropping into coverage.

He's strong against the run and, while his pass rushing repertoire still needs some work, is an ascending player who, with the help of defensive line coach Jerry Azzinaro and outside linebackers coach Bill McGovern, could certainly improve his hurry and sack numbers.

He also provides the versatility Kelly covets - he could play outside on first and second down, then rush the passer with his hand in the dirt in obvious passing situations, the way Cole, Graham and Barwin have done this season.

If he finds a way out of New York and the price tag isn't too exorbitant, he could be a fantastic fit on the outside in Philly.

And what about that lackluster secondary? Could Devin McCourty, a former cover corner turned free safety for the New England Patriots be the right guy to pair with Jenkins if he hits the open market?

The answer, class, is a resounding "yes."

The former first-round pick took the NFL world by storm, recording seven interceptions and 17 passes defensed and making the Pro Bowl as a corner in 2010, his first year in the league. The following season, the Patriots, facing the prospect of abysmal safety play, shifted their scheme and asked the 5-10, 195-pound McCourty to play more press coverage - the results were atrocious.

He was moved to safety for the final regular season game that year and stayed for the remainder of those playoffs. He returned to corner in 2012 and seemed to regain his initial 2010 form, but again poor safety play led to his being moved to the back-end of the secondary, where he continues to hold court.

Since 2013, McCourty has become an absolutely fantastic centerfielder, allowing the Patriots to play more single-high safety looks - of course having Aqib Talib, then Darelle Revis at corner certainly helps.

But it may also be Revis and cornerback Brandon Browner's success that could ultimately lead to McCourty's availability.

For the Eagles, adding a talented centerfield safety with a Pro Bowl cornerback past and the proven ability to play deep clean up for a press-man scheme on the outside would be an absolute coup. His addition would both allow Jenkins to more often play the versatile, in-the-box, slot role he's best suited to and make the corners on the outside, whoever they happen to be next season, look much, much better - no more plays over the top of Cary Williams wherein Nate Allen arrives seconds after the pass is already completed.

Both players will most likely be looking to break the bank and there's no guarantee either will actually be available.

But should they choose to test the waters of free agency, Philly should come calling - immediately - because beyond finding their franchise signal-caller, improving the defense via significant talent upgrades is the most urgently pressing need facing the Philadelphia Eagles in this, Kelly's first offseason of total control.