(973espn.com) - Maybe the most difficult decision the Eagles have to make in free agency concerns nickel back Patrick Robinson.

Playing on a one-year, prove-it deal last season, Robinson turned out to be one of the best slot cornerbacks in football, a position that is no longer a sub-package one as evidenced by the fact the veteran played in 68.9 percent of Philadelphia's defensive snaps (853 total).

The value was in incredible as Robinson finished last season with 47 tackles and four interceptions while his pick-six in the NFC Championship Game against Minnesota completely changed momentum in that one sending Philadelphia on to Super Bowl LII,  grading out as the sixth-best cornerback in the NFL by ProFootballFocus.com.

And the Eagles got all of that for $775,000.

From a production standpoint, it's inconceivable that Philadelphia wouldn't want Robinson back but the reality is that he will be 31 in early September and has had trouble in the past putting together two consecutive seasons.

Add in the expectation of a significant raise, the host of young corners at Jim Schwartz's disposal along with the Eagles' salary-cap difficulties and you have at least the recipe of Philadelphia coming to the conclusion that Robinson is a luxury.

The starters on the outside of the defense -- Jalen Mills and Ronald Darby -- as well as talented second-year players Sidney Jones and Rasul Douglas all project better on the outside vs. navigating the traffic in the slot with perhaps only Mills possessing the kind of skill set to move inside, which is an entirely different position requiring short-area quickness as well as the savviness to handle option routes run by disciplined receivers.

Versatile safety Malcolm Jenkins has also proven he can handle slot work but you don't want that being his full-time job.

From Robinson's perspective, he obviously fits in very well here and he is extremely close to Jenkins, who essentially recruited Robinson before last season.

The Eagles, however, have those money issues and are currently $10 million over the cap as the new league year is set to begin. The retirement of Donnie Jones gives Howie Roseman just under $2M back so other moves need to be made before a long-team deal with Robinson could be officially inked.

Talks between the two sides are currently ongoing before the legal tampering period begins on March 12. At that point others could get involved with both Arizona and Oakland both floated as potential matches, according to various reports.

"We are not going to make decisions, we are not going to get rid of good players because of our cap situation," the Eagles executive vice president of football operations said earlier this week at the NFL Scouting Combine. "That responsibility starts with me and making sure that we’re able to keep guys and sign good players and we’re not just doing things because of our cap situation."

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