What I'll be watching closely at Eagles training camp:

The Eagles defense enters training camp with three unanswered questions: 1) How will the cornerback situation shake out, particularly in the slot where Patrick Robinson's departure has created a vacancy? 2) Who will replace Mychal Kendricks as the WILL linebacker in base packages? And 3) who will be the No. 3 safety, behind starters Malcolm Jenkins and Rodney McLeod?

Ronald Darby, Jalen Mills and 2017 second-round pick Sidney Jones are competing for the two outside corner spots in the Eagles' base defense, which they play only about 20-25 percent of the time. The most popular scenario has Darby and Jones, who is coming off a ruptured Achilles, winning those two jobs, and Mills moving inside and replacing Robinson.

But Mills, who started 15 games outside last season, has no intention of surrendering an outside starting job to Jones without a fight.

Depending on the talented Jones' development this summer – he played in just one game as a rookie — Darby and Mills could wind up as the two corners in base, with Mills then sliding inside to the slot and Jones replacing him on the outside in sub-packages.

Other candidates for the slot job include 2017 practice-squadders De'Vonte Bausby and D.J. Killings, rookie fourth-round pick Avonte Maddox and Rasul Douglas. Bausby was very impressive in the non-contact spring workouts.

>>READ MORE: Carson Wentz's recovery isn't the only Eagles injury story entering camp

Defensive coordinator Jim Schwartz didn't settle on Robinson as his slot corner last year until two weeks before the regular season. But Robinson ended up being a major reason for the defense's success, particularly on third down.

The Eagles held opponents to a 66.4 third-down passer rating and intercepted nine third-down passes. That was the second most in the league.

Robinson's momentum-swinging 50-yard interception return for a touchdown against the Vikings in the NFC championship game came on a third-and-8 play.

Jenkins and McLeod are one of the best safety tandems in the league. But lack of depth is a concern at the position.

Schwartz will take a long, hard summer look at young players such as Tre Sullivan, Jeremy Reaves and Ryan Neal. If Schwartz doesn't like what he sees, the Eagles could coax 33-year-old Corey Graham back for one more year. The versatile Graham played 36 percent of the defensive snaps last season. His corner-safety versatility gave Schwartz the opportunity to play different defensive packages without changing personnel, which kept opponents off balance and unable to create mismatches.

The Eagles' linebacker situation is a little scary. On the day they released Kendricks, they also lost to injury Paul Worrilow, who figured to be the main backup to middle linebacker Jordan Hicks. Hicks is coming off a ruptured Achilles. If he can manage to stay healthy, a very big if given his medical history, the Eagles should be OK since they use so much two-linebacker sub-packages.

But if he gets hurt again, or something happens to Nigel Bradham, well, others, such as Kendricks' likely WILL replacement, Corey Nelson, and young backups such as Nate Gerry, Joe Walker and Kamu Grugier-Hill are going to have to step up.