As the beginning of the 2018 NFL season nears, fans in the City of Brotherly Love are still riding high after the Philadelphia Eagles won the team's first championship of the Super Bowl era. But as the Eagles attempt to become the first repeat champions in over a decade, a problem has arisen. Actually, several problems have arisen.

Injuries—a bunch of them.

The Eagles are banged up on the offensive side of the ball. Quarterback Carson Wentz is working back his way from last December's ACL tear. Backup (and Super Bowl darling) Nick Foles strained his shoulder in the preseason. Wideout Alshon Jeffery may not be ready for Week 1 after offseason shoulder surgery. Batterymate Nelson Agholor is nicked up as well.

It's looking more and more possible that the Eagles offense in the season opener against the Atlanta Falcons will be different from the unit that torched the Patriots in Super Bowl LII and ranked seventh in the NFL in 2017.

And that could put additional pressure on a Philadelphia defense that has undergone some changes of its own in the offseason.

As Dave Zangaro reported for NBC Sports Philadelphia on Monday, Wentz continues to progress in his rehab and is taking part in 11-on-11 drills.

"I want to be out there every day," Wentz said. "I want to be a full participant in every single thing. But that wasn't totally my call, and you just have to be smart in those situations. It was tough, but yeah, getting out there in the full-team drills, I definitely enjoyed it."

However, as has been the case all offseason, Wentz stopped short of saying he'd be under center for the season opener Sept. 6 at Lincoln Financial Field.

"I feel good," Wentz said. "Like I said, I think you guys see me out there. I have really no hesitation in the pocket when guys are around me. I feel really good, but it's going to come down to if they feel confident in contact and when that is. I can't say yet."

Even if Wentz does play in Week 1, given how late in the 2017 season his injury occurred, it's reasonable to assume he isn't going to be 100 percent. It's equally logical to figure that the weapons around the quarterback won't be either, given that Jeffery remains on the physically unable to perform list with Philly's "dress rehearsal" against the Cleveland Browns this Thursday.

The ground game is in similar shape. Last year's leading rusher (LeGarrette Blount) is in Detroit. The player penciled in to replace him (Jay Ajayi) is nursing a lower body injury of his own, although his availability for the opener isn't in question at present.

This isn't to say that the Eagles are going to implode offensively and morph into the 2017 Chicago Bears. But it could be a while before they are firing on all cylinders—or close to it.

Philadelphia has a slate that includes three games in the first five weeks with teams that won a playoff game last season (including an NFC title game rematch with the Minnesota Vikings), and that ramps up the pressure on the defense to carry the team—at least early on.

The strength of that defense—just as in 2017—is the front four. Simply put, the defensive line is loaded. It's also getting back arguably its best player. Per Zangaro, the team activated Brandon Graham from the PUP list earlier this week. The hero of the game-clinching drive in Super Bowl LII is working back into game shape after offseason ankle surgery.

Even if the 30-year-old Graham gets off to a slow start, the Eagles will be fine on the line. Veteran defensive end Chris Long is a capable fill-in. Derek Barnett, 22, showed flashes of his first-round talent as a rookie last year and should be ready for a larger role. And the Eagles more than made up for the loss of Vinny Curry by acquiring three-time Pro Bowler Michael Bennett from the Seattle Seahawks.

Add in tackles Fletcher Cox (a three-time Pro Bowler himself) and Timmy Jernigan, and the Eagles should again be tough to beat at the point of attack. No team in the league was harder to run on last season (79.2 rushing yards allowed per game). And Philadelphia should at least be able to match last year's 38 sacks.

Once you get past the first level, however, the questions start to mount.

There's talent at the linebacker position in Nigel Bradham and Jordan Hicks. But Bradham will sit out the season opener because of a suspension, and Hicks has missed at least half of two of his three seasons in the NFL. The 26-year-old told one of Zangaro's colleagues, Derrick Gunn, that this is a make-or-break season for him.

"Gotta stay healthy," Hicks said. "I gotta prove it. Obviously, that shows a lack of ability to have that faith in me that I'm going to be out there. That puts a chip on my shoulder. I embrace it. I gotta attack it. Gotta prove it."

Hicks' health is more important this year than in seasons past. With Mychal Kendricks now playing in Cleveland, there's precious little depth behind Bradham and Hicks. If one of those linebackers goes down, the Eagles could find themselves in trouble at the position.

The depth's better on the back end—maybe. In veterans Malcolm Jenkins and Rodney McLeod, the Eagles are set at safety, and the cornerback situation is better now than at this point a year ago, at least from a numbers standpoint.

Second-year pro Sidney Jones appears to be set for a larger role after essentially redshirting as a rookie while rehabbing a torn Achilles, and rookie Avonte Maddox has impressed so much that he's earned some first-team reps in the slot, per Eliot Shorr-Parks of NJ.com.

The outside spots look set, with Ronald Darby and Jalen Mills the likely starters. But as Jeff Kerr reported for 247Sports, defensive coordinator Jim Schwartz indicated the third spot remains up for grabs.

"I think just like everything, we're still a work in progress," Schwartz said. "Nothing has been settled there. Each guy brings a little bit different skill set, a little bit different strengths and weaknesses to the position. I think the competition is good."

Even so, no one is going to confuse the Eagles secondary with the Jacksonville Jaguars unit anytime soon. Philadelphia was 17th in the league in pass defense last year, allowing 227.3 yards per game—and that was with Patrick Robinson, who led the team with 18 passes defended but signed with the New Orleans Saints in March.

Mills is coming off a career year and shined at times, but he's not a shutdown corner. Jones and Maddox are untested and have struggled at times in the preseason. Philadelphia has potential there but also uncertainty. And the folks at Pro Football Focus aren't especially impressed by the secondary. As Brandon Lee Gowton reported for Bleeding Green Nation, PFF graded Philly's in the bottom half of the NFL—18th, to be specific.

In 2017, the Eagles were able to paper over the warts on the defense with great success, but that was because they had several things going for them.

First, Schwartz is good at what he does. The team also had a proven linebacker in Kendricks who could fill the void when Hicks got hurt, and its smothering run defense compensated for the occasional lapse in coverage. The offense would march right down the field and score if the defense faltered.

Now, however, Kendricks is gone. So is arguably the team's best cover man. The belief that Philadelphia's secondary will be better in 2018 is grounded as much in hope as empirical fact. And with the offense struggling to get healthy, there's no guarantee the Eagles will be able to win shootouts—especially early in the season.

None of this means the defense can't carry the team for a while. Schwartz has shown that he can craft one in which the whole is greater than the sum of its parts. And that line—man, oh man, that line is stacked. I ranked the Eagles first in Bleacher Report's NFL power rankings, and they will stay there through at least Week 1.

Such is the virtue of being the defending champs.

But if the Eagles don't start getting back offensive stars relatively soon, my confidence in that ranking is going to wane more than it already has. The NFC is a meat grinder this year, loaded with teams that appear to be as potent offensively as they are stifling defensively. And every team in the NFC East enters the year with one goal: Take down Philadelphia.

A one-dimensional Eagles team could find it tough sledding to hold them off and keep pace.