What will you be watching closely to determine if the Eagles are a Super Bowl contender again?

Four of our writers weigh in.

Mike Sielski

You mean, other than the strength, stability, flexibility, and contours of Carson Wentz's left knee? OK, I'll bite. Jim Schwartz's entire defensive philosophy is predicated on toughness, intimidation, and aggressiveness. Our guy beats their guy in a one-on-one matchup, and our guy sacks the quarterback or gobbles up the running back or blankets the wide receiver or delivers a bone-rattling hit. But if the preseason has been any indication, the Eagles will have a difficult time adjusting to the NFL's new guidelines for helmet-to-helmet contact.

Their first-team defense committed several personal-foul penalties because players, such as safety Rodney McLeod and linebacker Nigel Bradham, lowered their heads as they tackled opponents. Schwartz's defenses have tended to be infraction-heavy throughout his NFL coaching career, and last season, the Eagles committed 57 defensive penalties, third most in the league, and managed to overcome it. But if Schwartz's players can't figure out how to tackle without drawing a flag and costing themselves 15 yards of field position, it will be difficult for the defense to perform at a championship level again.

Jeff McLane

The Eagles won the title for many reasons, but the strength of their lines might have been the deciding factor. If they can't get pressure on defense, and if they can't protect on offense, they won't repeat.

The Eagles withstood the injury to left tackle Jason Peters last season, but the rest of the offensive line was healthy. On defense, only one player from the eight-man line rotation (Destiny Vaeao) missed more than two games to injury. The Eagles have as much depth up front as any team, should they suffer setbacks. But they can't lose multiple players for extended periods and expect to be championship contenders.

Even if they are healthy, success isn't guaranteed. What if Peters, at 36, were to suddenly play his age? What if left guard Stefen Wisniewski was to play like the reserve most of the NFL once deemed him to be? What if right tackle Lane Johnson, center Jason Kelce and right guard Brandon Brooks were to play a notch below their 2017 Pro Bowl levels? A combination of any of those scenarios could stunt the offense.

On defense, what if end Brandon Graham is slow to return to form after ankle surgery? What if tackle Tim Jernigan misses half the season after back surgery? What if end Michael Bennett and tackle Haloti Ngata struggle in a new scheme? What if end Derek Barnett doesn't take the next step forward?

Any of those circumstances are possible. The Eagles' success this season will depend on many factors. Quarterbacking and coaching are among the most important. But the health and performance of the big guys up front will go a long way in determining how far the Eagles go in 2018.

​Paul Domowitch

One of the things I'm going to be watching most closely is the Eagles' performance on third down and in the red zone, two areas critical to their success in 2017.

The Eagles finished first in red-zone offense last year after finishing 24th the year before. They converted a league-best 65.5 percent of their trips to the red zone into touchdowns. Carson Wentz led the league in red-zone passing with a 116.0 rating. Tight end Zach Ertz had a career-high eight touchdown catches, all of them in the red zone.

The Eagles were the only team in the league that didn't throw an interception or allow a sack in the red zone. The Eagles finished eighth in third-down offense (41.7%), but were second through the season's first 15 weeks. Before he got hurt, Wentz was leading the league in third-down passing (123.6 rating). A league-high 14 of his 33 touchdown passes came on third down.

In the postseason, the Eagles owned third down. Nick Foles completed 26 of 32 third-down passes in the playoffs, including an unbelievable 11-for-14 third-down performance against the Patriots in the Super Bowl. Foles had a 158.1 third-down passer rating in the playoffs, which is the best in NFL history.

One of the Eagles' most significant offseason losses was cornerback Patrick Robinson. Robinson, who signed with the Saints, stepped in and did an outstanding job as the team's nickel corner last year. He helped solidify the pass defense and had that momentum-shifting interception return for a touchdown against the Vikings in the NFC championship game.
He is expected to be replaced by talented second-year player Sidney Jones. With their schedule loaded with exceptional slot receivers, the Eagles need Jones to pick up where Robinson left off.

David Murphy

While there is no scientific law that says the universe might one day produce a humanoid life form that transcends physical mortality, the historical record suggests that Jason Peters will one day reach a point at which he is no longer capable of winning that whole F = MA equation. At 36, the future Hall of Famer is at that point in his career when any season could be his last. That the Eagles played as well as they did in their 12 games without him last season was almost as remarkable as the way they played after Wentz went down. The performance of the offensive line down the stretch was the single greatest factor in their Super Bowl run. In 2018, it remains the unit that will serve as the greatest bellwether for their ability to repeat.

On the defensive side of the football, the area to monitor is the middle of the field, particularly against the run. Defensive tackle Timmy Jernigan, a revelation in 2017, seems destined to start the season on the Non Football Injury list (back surgery), and middle linebacker Jordan Hicks is returning from a ruptured Achilles. The Eagles last season held opposing rushers to 3.8 yards per attempt, the sixth-best mark in the NFL. At the same time, opponents ran the ball just 337 times against them, the lowest total of any team since 2010, and the fourth lowest since 1983. The ability to stop the run magnifies the pass-rushing ability of the front four, and it will be one area worth watching through the early part of the season.