Pro Football Focus believes the Philadelphia Eagles’ additions this offseason have help them build a top 10 roster in the NFL.

But between adding speed at wide receiver and adding depth to its defense with Darius Slay, Javon Hargrave and a returning Malik Jackson, PFF grades the Eagles roster in the top 10 of the NFL. PFF’s Ben Linsey ranked Philadelphia with the 10th-best group of players entering 2020, based on the projected grades of their starting players.

First, the the teams biggest strength:

The Eagles are one of the strongest teams in the NFL in the trenches. As a team, they finished the season with PFF's highest-graded offensive line, and their defensive line ranked fourth behind only the Steelers, 49ers and Rams. The defensive line is a group that should continue to improve with the additions of Javon Hargrave and a healthy Malik Jackson.

Linsey mentions the Eagles strength in the trenches with their offensive line being the highest-graded in the NFL in 2019.

The Eagles’ biggest concern is an easy one - linebacker.

Philadelphia drafted Davion Taylor in the third-round and signed free agent Jatavis Brown, but neither are projected starters.

Back are Nate Gerry and T.J. Edwards.  That duo are expected to get the most snaps at the linebacker position, making it a big question heading into 2020.

Linebacker is still a question mark for Philadelphia. Nathan Gerry figures to be atop the depth chart after more than 600 snaps of average play in 2019, but there's much less clarity behind him. Can T.J. Edwards break out after earning an 83.4 overall grade on just over 100 snaps last season? Will Jatavis Brown win a starting job after shaky play led to his role getting significantly reduced in 2019 with the Chargers? Rookie Davion Taylor will have a chance at playing time early, too. It's a group that still doesn't have much definition on what should be an improved defense overall.

The linebacker position enters 2020 with clearly the most unknowns, and questions.  While there is some interesting talent, they are hardly considered to be a strength of the roster.

As for the biggest X-Factor?  PFF thinks Darius Slay is better than his 2019 PFF grades show.

Darius Slay‘s PFF grade in 2019 doesn't represent the kind of player that he has been throughout his career. The first thing to note is that he played a difficult role in Detroit, consistently shadowing the opposing team's best receiver in man coverage. Despite that, Slay came in as the fourth-most valuable cornerback in the NFL in 2014-18 per PFF WAR (wins above replacement), and his 74 forced incompletions over that stretch were the most in the NFL. Expect him to bounce back and give a big boost to that secondary.

If he is an upgrade to the cornerback position, he should clearly be the best player Jim Schwartz has had at that position since he took over as defensive coordinator in 2016.