Patriots, Cowboys, Lions lead the list of best offensive lines

All team sports are interdependent entities to a greater or lesser degree, but it's hard to imagine a group of athletes relying on each other more than an NFL offensive line. Most great lines will have their share of superstars to be sure, but you'll also see outstanding run blocking and pass protection from groups of linemen who aren't that far above league average; they just happen to be in the right scheme for their talents and understand precisely when they're supposed to be doing.

Conversely, there are lines with mammoth and physically gifted individuals who fall flat on their faces more often than not, due to poor planning and schematic anxiety.

So, when ranking the league's top 10 offensive lines, many factors are taken into consideration. Certainly, the numbers on sacks allowed, yardage gained, blown blocks and penalties are important, but you also have to look at the tape to see which lines are aided greatly by the processing speed of their quarterbacks and the pure power and agility of their running backs. We're also looking at additions and subtractions, as well as regression from one year to the next, and regression can happen quickly. To wit, neither the Baltimore Ravens nor the San Francisco 49ers, who met in Super Bowl XLVII with the relative strengths of their lines as major factors, made the cut in our projections.

POSITION RANKINGS:Safeties|Corners|D-tackles|Pass rushers|LBs

(Note: Unless otherwise specified, all stats come from Football Outsiders and Pro Football Focus. An explanation of FO's offensive line stats can be found here.)

10. Philadelphia Eagles -- Second-year right tackle Lane Johnson will miss the first four games of the 2014 season after violating the league's policies on performance-enhancing substances, and Johnson really could have used the work. He appeared overmatched for the most part in pass protection, though he improved as the season progressed. He'll most likely be replace by Allen Barbre in the short term. Left tackle Jason Peters didn't have his best season, but held up well in a scheme that tests linemen to their limits with zone concepts and wide splits. The superstar here is left guard Evan Mathis, who adapted perfectly to the complications inherent in Chip Kelly's offensive structures. Center Jason Kelce and right guard Todd Herremans filled out a line that stayed on the field all the way through the regular season and into the playoffs. If they can do that again, and can further integrate their talents into what Kelly does, this entire offense could be ridiculously good.​

9. Cleveland Browns -- Who knows who's going to be their quarterback in 2014... but whether it's Brian Hoyer or Johnny Manziel (or some unholy combination thereof), those signal callers will have fine protection. We can start with left tackle Joe Thomas, who hasn't missed a game since the team made him the third overall pick in the 2007 draft. He's still among the best pass protectors in the game. The Browns also came to terms on a new deal with center Alex Mack, recognized as a key player in this franchise's future development. Replacing John Greco as the primary left guard will most likely be Nevada rookie Joel Bitonio, a quick, strong player with plus attitude. Greco is expected to move to right guard, while Mitchell Schwartz remains at right tackle ... and that may not be good news for the Browns. Schwartz has been a walking disaster, especially in pass protection, since the Browns took him in the second round of the 2012 draft. New head coach Mike Pettine believes that Schwartz will thrive in offensive coordinator Kyle Shanahan's zone-blocking system. We think there's nowhere to go but up.

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8. Green Bay Packers -- The strength of the Packers' line is inside, where guards Josh Sitton and T.J. Lang are especially good on the move. Sitton in particular is one of the NFL's best, and he saw no lag in performance when moving from right to left guard Center Evan Dietrich-Smith moved on to Tampa Bay, and he'll likely be replaced by someone in a bevy of unknown prospects -- J.C. Tretter, Corey Linsley and Garth Gerhart are the probables. At left tackle, the Packers hope for greater things from David Bakhtiari, who saw 1,119 snaps as a rookie fourth-rounder and fit in some really good play around the usual rookie mistakes. Bryan Bulaga, who lost the entire 2013 season to a torn ACL, moves back to right tackle.

7. Denver Broncos -- Quarterback-aided line No.1, but given the season-ending knee injury Ryan Clady suffered in Week 2, we'll give the Broncos' front five credit. Clady is this line's best player, but Chris Clark filled in ably enough, and he'll be a better fit at right tackle. Orlando Franklin, who was never meant to be a right tackle (he gave up the pressure that led to Seattle's pick-six in the Super Bowl) will move inside to left guard, where his mauling temperament fits perfectly. Former Chargers guard Louis Vasquez, who had the fewest blown blocks per snap of any guard in the league by a considerable margin, adds his considerable talent to a line that is virtually guaranteed to be better than it was in 2013, when Denver proved to be the most prolific offense in NFL history. A scary thought for the defenses facing it.

6. New Orleans Saints -- Quarterback-aided line No. 2, but there's a lot more here than just Drew Brees being really smart. Right guard Jahri Evans has been one of the best in the business for a long time, and though he did see an increase in blown blocks last season, he should have a few good years left. The same can be said of left guard Ben Grubbs. Right tackle Zach Strief had a great season, but the position of interest in left tackle, where rookie Terron Armstead played extremely well late in the season after Charles Brown was benched. Armstead was rough early on when Carolina end Greg Hardy dominated him, but he rebounded nicely, and he has the strength and speed to be a perfect fit in Sean Payton's diverse passing game. At center, the idea is to give Jonathan Goodwin a shot, but at age 36, Goodwin's best days are behind him.​

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5. Cincinnati Bengals -- Bengals lineman Andrew Whitworth may have been one of the 10 most valuable players in the league last year. When he was recovering from offseason knee surgery, the Cincinnati line suffered right along with him. But things turned around when Whitworth was healthy, and the Bengals went from 3.82 Adjusted Line Yards in the first half of the season to 4.22 from then on. And in the last six games of the Bengals' season, including the postseason, Whitworth kicked inside to left guard from left tackle and held things together just as well. Whitworth did so after Clint Boling was hurt, and this allowed Anthony Collins to fill in well enough to get a big free agent deal to play in Tampa Bay. Collins will be replaced by former Packers bust Marshall Newhouse (formerly of the Packers, but a bust until further notice). Right tackle Andre Smith continued to play extremely well in the run game and give up pressures in pass pro, but that's the way it goes. The question here will be at center, where Trevor Cook will be replaced by either Russell Bodine, Trevor Robinson or Mike Pollak.

4. San Diego Chargers -- In 2013, the Chargers switched players at every position but center, and it all worked very well for two reasons: an upgrade in overall talent, and a new offense designed by head coach Mike McCoy and offensive coordinator Ken Whisenhunt that had Philip Rivers playing much faster. Left tackle King Dunlap and right tackle D.J. Fluker are more ginormous road-graders than agile lateral movers, but they both worked very well in this system, and they were two key components in the career year put forth by running back Ryan Mathews. Center Nick Hardwick will come back for one more season, and rookie Chris Watt from Notre Dame is projected to replace him over time. Jeromey Clary played estimably enough at right guard, while Chad Rinehart and Johnnie Troutman alternated at left guard in a line that had more talent than the previous coaching staff allowed it to show, and benefited from several smart new moves.

3. Detroit Lions -- The Lions' uptick in pass protection was indicated with one amazing stat -- in 634 passing attempts, Matthew Stafford was sacked just 23 times. Detroit's Adjusted Sack Rate was second in the league behind only Denver's, and Stafford doesn't help his lines nearly as much as Peyton Manning does. The most pleasant surprise in 2013 was the play of rookie right guard Larry Warford, who brought it at a Pro Bowl level at the price of a third-round pick. Warford didn't allow a single sack in 1,126 snaps, and it could be argued that he should have been Rookie of the Year. The Lions also benefited from the play of undrafted rookie LaAdrian Waddle, who will see a lot more snaps than the 536 he took in 2013. The other pleasant surprise was the play of left tackle Riley Reiff, who looked like a man in control of his position in his second NFL year. Reiff still struggles with edge rushers and gives up too many pressures, but he played well through a hamstring injury in the second half of the season. Center Dominic Raiola and left guard Rob Sims are relatively reliable veterans, but make no mistake -- Warford is the star here. ​

2. Dallas Cowboys -- Whatever regression may have come at other positions due to Jerry Jones' capricious personnel machinations, the Cowboys have put together a pretty impressive line, and the left side looks particularly strong. If left tackle Tyron Smith isn't the best young player at his position (he's only 23,  and won't turn 24 until Dec. 12), he's certainly on a very short list. While his pass protection still needs a bit of refinement, there's a reason that no team ran to the left end and left tackle areas more than Dallas (42 percent of the time). Center Travis Frederick, the subject of much controversy in the 2013 draft when the Cowboys took him in the first round despite the fact that many had a third-round grade on him, played more than solidly and helped the Cowboys put together the kind of power running they hadn't seen since the days of Marion Barber. The Cowboys' 2014 first-round pick Zach Martin of Notre Dame played left tackle in college, but he can play the left and right guard positions at the next level, and could sub at center or right tackle in a pinch. Martin is powerful but athletically limited. Doug Free, the current right tackle, had a fine season, though he's a bit too penalty-prone at times. The same could be said of left guard Ronald Leary. Right guard Mackenzy Bernadeau may get the primary reps at the inside spot Martin doesn't take. It's surprising for a franchise that doesn't generally appreciate depth, but yes, Dallas' offensive line is one of the best around.​

1. New England Patriots -- The main point of flux in this line is the replacement of retired coach Dante Scarnecchia with ex-Jets line coach Dave DeGuglielmo. Scarnecchia was a demigod on Foxboro and he'll definitely be missed, but the good for the Pats is that they look to start the same five guys who took the most snaps on their 2013 line, and when healthy, that line was one of the team's real strengths. Even with the skill players around them in constant flux, New England only dropped from first to fourth in Adjusted Line yards, and they led the way for the Patriots to gain 4.69 running back yards per carry, the highest total the team has had since 1996. There was a drop in Adjusted Sack Rate from fifth to ninth, but that can be credited as much to the fact that Tom Brady had to spend so much time getting on the same page as his mystery receivers as anything else. If tackles Sebastian Vollmer and Nate Solder can return to full heath and total playing time, and veteran Logan Mankins keeps up his relatively high level of play, it will make things even easier for center Ryan Wendell, who had the team's highest blown block rate, and right guard Dan Connolly, who had his own pass protection issues. You'll hear at times that Brady makes things so much easier for his line, but he didn't really have a chance to do that in 2013, and this might be the most efficient run-blocking line in the NFL.