PHILADELPHIA (973espn.com) - Ronald Darby's time in Philadelphia has been star-crossed.

A valuable trade pickup before the 2017 season from Buffalo, there has been a thick dossier put together on the former Florida State star over his short two years at the NocaCare Complex, the dislocated ankle, a torn ACL, ping-ponging from the right corner position to the left and back again, a Super Bowl ring and the acknowledgment from many in Philadelphia's organization that Darby is unquestionably the team's top outside option at one of the most important positions in the modern game.

Yet the overwhelming consensus as we speed to the new league year on March 13 is that the cap-strapped Eagles will be unable to keep a 25-year-old still on the upswing when it comes to the trajectory of his career.

Typically, CBs in their mid-20s with high-level skills sets never hit free agency and the lone hope for the Eagles is that the injuries, the ankle which cost Darby 10 games during the Super Bowl season and the ACL which shut him down after nine games in 2018, will make Darby's rate more manageable.

Those pointing to the cost-effective extension Tavon Young signed in Baltimore [three years with only $13 million guaranteed], are not recognizing the differences in the pay scale between nickel backs and outside corners. As evidence of that Spotrac.com has estimated Darby's market value at an astounding $13.4M per year.

The injuries will certainly knock down the length of the contract on that projection and perhaps the annual value but not nearly as far as some believe.

When you look at the 2019 free-agency class at CB where Darby and another injury-prone player in Jason Verret, are the most skilled projected to hit the market you can start to envision the demand quickly overwhelming the supply.

The NFL mindset at CB was best exemplified in Minnesota last year when Mike Zimmer and the Vikings raised some eyebrows in the 2018 draft by choosing Mike Hughes in the first round despite possessing two former first-rounders at the position, Xavier Rhodes, who was coming off an All-Pro season, as well as Trae Waynes, plus the ageless Terence Newman and emerging former second-round pick Mackensie Alexander.

"A famous, old coach called me this morning and said that one of the reasons he likes me is because he understands that you can never have too many cornerbacks," Zimmer said after the draft. "There's a commercial on TV right now where the lady asks this guy how many guns he needs, and he says ‘Just one more.' That's how we feel about corners -- just one more. So as many times as we can find guys that can cover around here, the more we want."

Turns out Hughes' rookie season was cut short by an ACL tear, Rhodes suffered through an injury-plagued season where he was generally on the field but far less than 100 percent, Waynes had concussion issues on two occasions and Father Time finally ran down Newman who retired resulting in undrafted rookie free agent Holton Hill playing major reps.

The moral of that story is that you can never have enough CBs in NFL and talented ones like Darby will always have a market.

-John McMullen covers the Eagles and the NFL for 973espn.com. You can reach him at jmcmullen44@gmail.com or on Twitter @JFMcMullen