PHILADELPHIA -- As Chip Kelly cuts his roster to the 53-man limit, here are a couple of other things that should be on the coach’s to-do list:

The secondary. The Eagles went into their final preseason game unsure who their nickel cornerback and backup safeties would be. That is exactly how they opened training camp, partly because Kelly decided a conditional draft choice was more valuable to him than Brandon Boykin.

Overall, Kelly’s remaking of his secondary still feels incomplete. Maybe Kelly went into the offseason thinking Nolan Carroll was a starting cornerback (despite backing up Bradley Fletcher last year) and that injured Giants cornerback Walter Thurmond would make an excellent safety. Maybe Kelly has improvised after spending $63 million to sign Byron Maxwell.

But will that improvisation work? It might. But for now, the Eagles still aren’t sure who will replace Boykin as the nickel corner. Their fallback position has been to have Thurmond or Malcolm Jenkins do it. And after four preseason games, defensive coordinator Bill Davis was still talking about that option.

But who will play safety if one of the safeties moves to cornerback? That matter also appears unsettled.

Kelly succeeded in adding fresh talent to his secondary. Maxwell, Thurmond, Eric Rowe and Randall Evans can certainly develop. But do they have the six reliable defensive backs they need, in the proper roles, to field a legitimate secondary?

That is undetermined 10 days before the season opens against Matt Ryan, Julio Jones, Roddy White and the Falcons.

Offensive line depth. Back in June, Kelly cut Pro Bowl guard Evan Mathis and signed former Seahawks guard John Moffitt after the offseason workouts were over.

It appeared that the coaching staff hoped Moffitt could be the player he was before getting into legal trouble and retiring suddenly two years ago. That would make Moffitt a candidate to start at guard or provide a steady backup.

But Moffitt looked rusty at the beginning of camp and he looked almost as rusty at the end of the preseason. Allen Barbre is the starting left guard. The competition at right guard never really materialized, with Andrew Gardner playing with the first team throughout the preseason.

That can be fine, as long as the starting five remain healthy. If they don’t, the Eagles could have trouble. Matt Tobin and Josh Andrews may be good enough to fill in capably, but that’s a large risk when you’re talking about protecting Sam Bradford and his left ACL.

Kicker concern. Kelly said Cody Parkey is fine. Cody Parkey said Cody Parkey is fine. But the second-year kicker missed a couple of kicks in the first preseason game, then missed the last two games with a groin injury.

With 10 days until the season opens in Atlanta, Parkey has time to be at 100 percent health-wise. But will he have enough opportunities to kick the ball and get his mechanics where they need to be?

This isn’t something to push the panic button about, but it is worth keeping an eye on.

Rust never sleeps. Kiko Alonso played eight preseason downs after missing the entire 2014 season with a torn ACL.

DeMeco Ryans was on the field for 20 plays, Mychal Kendricks for 26. Sam Bradford took 32 snaps from center. DeMarco Murray played on 22 offensive plays.

If the purpose of the preseason is for players to knock the rust off and get up to regular-season speed, then there has to be some concern that these key Eagles won’t be completely ready. If you believe the preseason is unimportant, then why play them at all?

Again, we’re not sounding any major alarms here. But it won’t be shocking if some of these players are talking later in the season about getting off to a slow start because of their limited preseason work. After all, rust never sleeps.