1 Seattle Seahawks
2014 Ranking: 1
Top five players: Richard Sherman, Earl Thomas, Marshawn Lynch, Jimmy Graham, Russell Wilson
Starters who should be upgraded: Lemuel Jeanpierre, J.R. Sweezy, Justin Britt, Tony McDaniel
Analysis: The best roster in football belongs to the Seahawks. The team, which was littered with injuries at the time, came up one play short of winning back-to-back Super Bowls, and that had more to do with a questionable play call and a fantastic defensive play than any sort of roster weakness.
The offensive line remains below average at best, but Wilson, Lynch and now Graham give the Seahawks weapons perfectly suited to make up for any blocking issues, especially when their read-option plays are added into the equation. Lynch broke 130 total tackles last season, including the playoffs, while no other back got near 100.
The Legion of Boom was very banged up by the end of that Super Bowl, but Sherman and Thomas remain elite talents, and there are quality players all over the defense. Even free-agent pickup Cary Williams, much maligned in Philadelphia, could have a pretty good year in a defense that puts better talent around him and supports his aggressive play. With the roster in this kind of shape, the Seahawks aren't going anywhere for a while.
2 Green Bay Packers
2014 Ranking: 8
Top five players: Aaron Rodgers, Randall Cobb, Josh Sitton, Jordy Nelson, Clay Matthews
Starters who should be upgraded: Letroy Guion, B.J. Raji, Sam Barrington, Davante Adams
Analysis: Top to bottom there are several teams with more talent than the Packers, but the boost they receive for having Rodgers -- the league's best quarterback -- is substantial. Top passers can cover up a lot of cracks, and quarterbacks as good as Rodgers can elevate a roster from good to excellent.
If there is a worry for this team, it remains up the middle, where the retention of both Guion and Raji is a concern given their play last season. On offense, Rodgers is helped by having a pair of elite targets -- Nelson and Cobb -- while Eddie Lacy is capable of raising himself to the top tier of running backs with a little more consistency.
3 Baltimore Ravens
2014 Ranking: 16
Top five players: Marshal Yanda, Ricky Wagner, Kelechi Osemele, Terrell Suggs, Brandon Williams
Starters who should be upgraded: Courtney Upshaw
Analysis: There's a lot to like about the Baltimore roster. No, Joe Flacco isn't elite, but the offensive line became one of the league's best a year ago and that paved the way for an excellent season from running back Justin Forsett, who returns for 2015. Rookies have the potential to make a big impact on this team: Wide receiver Breshad Perriman and tight end Maxx Williams could become two of the Ravens' top three targets on offense by season's end.
The defense is not quite what it once was, but it's still full of good players. Cornerbacks Jimmy Smith and Lardarius Webb should be better if they can just stay healthy. Defensive tackle Haloti Ngata has departed, but Brandon Williams and Timmy Jernigan played very well last season and should fill that void.
4 New England Patriots
2014 Ranking: 6
Top five players: Devin McCourty, Tom Brady, Rob Gronkowski, Dont'a Hightower, Jamie Collins
Starters who should be upgraded: Alan Branch, Bryan Stork, Ryan Wendell
Analysis: If nothing else, the Patriots made some of the most interesting roster moves in the game. This offseason they began by dismantling the secondary that was the backbone of their Super Bowl-winning defense. Gone are Darrelle Revis and Brandon Browner, two players who played a big role in New England's success last year. Instead of investing heavily at the position in free agency or the draft, the Patriots didn't select a cornerback until Darryl Roberts in the seventh round -- two rounds after selecting a long-snapper from Navy.
Elsewhere, the team has talent in key places, with the Brady-Gronkowski connection enough to create a high-powered offense on its own.
5 Denver Broncos
2014 Ranking: 3
Top five players: Von Miller, Chris Harris Jr., Malik Jackson, Demaryius Thomas, C.J. Anderson
Starters who should be upgraded: Gino Gradkowski, Derek Wolfe, Sylvester Williams
Analysis: Denver is still able to maintain a quality roster around high-priced quarterback Peyton Manning thanks to some smart drafting and having a few key players on very cheap contracts (such as running back Anderson). Outside linebacker Miller and cornerback Harris are elite players at key positions, and the Broncos have found quality players across other important spots like defensive end Jackson.
The concern for this roster is the offensive line, which has become even more acute a problem since Ryan Clady went down this offseason with a season-ending injury. Clady hadn't been playing to his previous level in some time, but rookie Ty Sambrailo out of Colorado State represents a major downgrade as he adjusts to a much higher level of competition. Louis Vasquez now remains the only quality player on what used to be one of the league's better lines.
6 Philadelphia Eagles
2014 Ranking: 5
Top five players: Jason Peters, Evan Mathis, DeMarco Murray, Fletcher Cox, Brandon Graham
Starters who should be upgraded: DeMeco Ryans
Analysis: Head coach Chip Kelly's offseason overhaul still has the Eagles in good shape, particularly along the offensive line, which is one of the NFL's best units when healthy. Adding Sam Bradford at quarterback probably doesn't provide much of a change in production from what Kelly has gotten out of Nick Foles and Mark Sanchez the past two years, and that's not necessarily a bad thing. At running back, Murray and Ryan Mathews combine with the versatile Darren Sproles to give the offense multiple options.
Defensively, the Eagles are led by defensive end Cox up front, while outside linebacker Graham will get his first extended look as a starter after five productive seasons in a part-time role. The addition of Kiko Alonso will help the middle-of-the-field coverage, while Mychal Kendricks continues to improve every year. The position to watch is cornerback, where Byron Maxwell comes over from Seattle, and Nolan Carroll will battle rookies Eric Rowe and JaCorey Shepherd for the starting role vacated by the departing Bradley Fletcher, who was coming off a disastrous 2014.
7 Detroit Lions
2014 Ranking: 11
Top five players: Calvin Johnson, Golden Tate, Glover Quin, Ezekiel Ansah, Larry Warford
Starters who should be upgraded: Brandon Pettigrew, Travis Swanson, Bill Bentley, Jason Jones
Analysis: The Lions have done a really good job of upgrading their roster the past few seasons. Elite talents like Johnson remain, but they have been augmented by a steady influx of talent on both sides of the ball: Wide receiver Tate, free safety Quin, defensive end Ansah and guard Warford.
As a result, the Lions have a roster with few holes, even after the departure of Ndamukong Suh in free agency. They nearly won a close, controversial playoff game last season, and it won't take much of an improvement for Detroit to be a real contender in 2015.
8 Minnesota Vikings
2014 Ranking: 29
Top five players: Adrian Peterson, Harrison Smith, Sharrif Floyd, Everson Griffen, John Sullivan
Starters who should be upgraded: Brian Robison, Chad Greenway, Matt Kalil
Analysis: Getting Peterson back in the fold will do wonders for this team, but the Vikings' biggest reason for optimism is how Teddy Bridgewater finished the 2014 season at quarterback. Over the final five weeks, he was PFF's highest-graded passer, one spot better than Rodgers. Over the final six games, he was second only to Drew Brees. If he plays in 2015 the way he ended 2014, the Vikings are a legitimate threat to make the playoffs (particularly if Kalil rebounds from a poor 2014 campaign).
Under Mike Zimmer, the defense has taken significant steps forward and could get even better with another step from guys like Xavier Rhodes, who flashed elite talent last season.
9 Cincinnati Bengals
2014 Ranking: 7
Top five players: Carlos Dunlap, Geno Atkins, Vontaze Burfict, Andrew Whitworth, A.J. Green
Starters who should be upgraded: Domata Peko, A.J. Hawk, Rey Maualuga, Russell Bodine, Mohamed Sanu
Analysis: The Bengals are a team with a lot of talent that is being weighed down by their quarterback. Andy Dalton can be awful one week and fantastic the next, and while the Bengals have done well to surround him with good weaponry and blocking, he hasn't proven he can be a consistently effective NFL quarterback.
Cincinnati's defense has a lot of talent, especially if Atkins gets back to his best after a down 2014. The linebacker corps is a concern, with Burfict coming off a knee injury.
10 New Orleans Saints
2014 Ranking: 4
Top five players: Drew Brees, Junior Galette, Jairus Byrd, Zach Strief, Max Unger
Starters who should be upgraded: Nick Toon, Erik Lorig, Dannell Ellerbe
Analysis: The Saints have a rebuilt offensive line that has the potential to be excellent. Unger, acquired in a trade with Seattle, gives New Orleans one of the league's best run-blocking centers, and rookie tackle Andrus Peat allowed just nine total pressures in his final season at Stanford. That overhaul came at the cost of Jimmy Graham, of course, but the Saints still have Brees and a loaded backfield to help make up for it.
Galette's offseason pectoral injury bears monitoring, as he is the only proven pass-rusher they have at the moment. If he misses significant time, rookie outside linebacker Hau'Oli Kikaha might have to play a major role.