Discussions to determine the best and worst offensive lines in the NFL are about as clear and convincing as the statistics that accurately reflect the effectiveness of this important unit.

Exactly. There is no such stat.

Oh, there are imaginative equations that include quarterback drop-backs, coverage sacks, down-and-distance and number of pass plays called on a rainy day. Well, we're kidding about the rainy day part, but the point remains, stats don't tell the story for most O-lines except for some extreme cases -- the very, very good or bad. That is because there are too many "yeah-buts" attached to most statistics used to measure offensive lines.

Sacks yielded per drop-back or yards per rush are often referenced in an attempt to quantify the work of offensive linemen.

A team with numerous sacks might point to contributing factors: receivers who can't get open, quarterbacks (especially inexperienced ones) who hold onto the ball too long or go through their progression of reads too slowly. ... and, conversely, a low number of sacks may not say much about the front wall if the quarterback is named Dan Marino or Peyton Manning, two of the quickest triggers in NFL history.

And yards per carry can be skewed by the breakaway talents of a gifted back who gains yards despite the inability of his offensive line.

Classic chicken-and-egg stuff.

Regardless, reporters covering each team for The Sports Xchange were asked to analyze offensive lines. The results are presented here team-by-team to be combined with whatever stat or stats readers prefer in an attempt to give some rank and order to the subject.

Generally speaking, which is a copout way to avoid the truthful IMO, Dallas, San Francisco, New England and Philadelphia have good offensive lines and Denver may or may not depending on how much weight is placed on the Manning factor. Seattle, the Super Bowl champion, is among the worst two or three in the league.

And that sad ranking of the Seahawks' line makes running back Marshawn Lynch and Beast Mode all the more impressive. And can't you just hear those intense 12th-man fans from Seattle objecting to such a low ranking, with a "yeah, but two key linemen were injured most of last season." And so it goes.

Here is analysis from TSX reporters on each team's offensive line for fans to mix and match with whatever statistics they deem appropriate. Teams are listed alphabetically, which may be the only inarguable way to rank offensive lines:

ARIZONA CARDINALS

--OFFENSIVE LINEMEN: Starters - LT Jared Veldheer, LG Jonathan Cooper, C Lyle Sendlein, RG Paul Fanaika, RT Bobby Massie. Backups - G/T Nate Potter, G Earl Watford, T Bradley Sowell, G/C Ted Larsen, G/C Anthony Steen, C Philip Black.

There will be at least three new starters and possibly four. Left tackle has been a need for years, and the Cardinals signed Veldheer in free agency. They think he can be elite. Cooper, the seventh overall pick in 2013, didn't play as a rookie after suffering a broken leg. He wasn't 100 percent in offseason practices, but coaches think he will be by the start of training camp. Sendlein is a smart, solid veteran who holds the unit together. Fanaika is being challenged by Earl Watford. No matter who wins the job, the position will be a weakness until someone proves otherwise. Massie emerged from the offseason as the starter, but his hold on the job is tenuous. He's being challenged by Sowell and Potter, and the Cardinals have also looked outside for help. They worked out Tyson Clabo in June and re-signing Eric Winston, last year's starter, remains a possibility.

ATLANTA FALCONS

--OFFENSIVE LINEMEN: Starters - LT Sam Baker, LG Justin Blalock, C Joe Hawley, RG Jon Asamoah, RT Jake Matthews. Backups - TLamar Holmes, T Ryan Schraeder, T Terren Jones, C Peter Konz, C James Stone, G Mike Johnson, G Gabe Carimi, G Adam Replogle, G Harland Gunn.

The Falcons mis-assessed the readiness of Konz and Holmes to take over for Todd McClure and Tyson Clabo last season. Coupled with weak play by right guard Garrett Reynolds, who was released, and retread tackle Jeremy Trueblood and the Falcons were leaking oil before most games started. The unit gave up 44 sacks and couldn't open up any holes in the run game as the Falcons were last in the league in rushing at 77.9 yards per game. Asamoah was added in free agency and Matthews was selected sixth overall in the draft. The Falcons are hoping that Baker (knee surgery) can return to good health. New position coach Mike Tice will try to whip the unit into shape.

BALTIMORE RAVENS

--OFFENSIVE LINEMEN: Starters -- LT Eugene Monroe, LG Kelechi Osemele, C Jeremy Zuttah, RG Marshal Yanda, RT Rick Wagner. Backups -- LT James Hurst, LT David Mims, LG John Urschel, C Gino Gradkowski, C Reggie Stephens, RG A.Q. Shipley, RG Will Rackley, RT Ryan Jensen, RT Jah Reid, RT Parker Graham, RT Brett Van Sloten.

The Ravens re-signed Monroe as the cornerstone of their line to a $37.5 million contract. Osemele looked good during the spring after undergoing back surgery last fall. Zuttah should be an upgrade at center after arriving via an offseason trade. Yanda is the lone Pro-Bowl selection and is the mainstay of the line. Wagner is the biggest question mark as a first-time starter at right tackle. Gradkowski is the primary backup inside after starting every game at center last season.

BUFFALO BILLS

--OFFENSIVE LINEMEN: Starters -- LT Cordy Glenn, LG Chris Williams, C Eric Wood, RG Kraig Urbik, RT Erik Pears. Backups - G Doug Legursky, T Cyrus Koundjio, OL Antoine McClain, T Chris Hairston, G J.J. 'Unga, G Mark Asper, G Cyril Richardson, T Seantrel Henderson, OL Edawn Coughman, C Macky MacPherson.

The emphasis for the Bills up front was to get big, athletic men, and that's what they did in the draft by choosing Kouandjio, Richardson and Henderson. Taking all 15 men into account, they now have the heaviest line in the NFL. Williams was a free-agent signing, but he really hasn't distinguished himself in the NFL. Glenn and Wood are excellent, and Urbik is a grunt who quietly gets the job done. The big battle will be at right tackle where Kouandjio was drafted to replace Pears. However, he still has to beat out the veteran. The battle for backup spots will be hot, and it's tough to tell who will emerge, but if Henderson can impress, the Bills - based on his potential - might have to keep him. There's a chance Pears will get cut, so that would open up a backup tackle spot.

CAROLINA PANTHERS

--OFFENSIVE LINEMEN: Starters - LT Nate Chandler, LG Amini Silatolu, C Ryan Kalil, RG Trai Turner, RT Byron Bell. Backups - C Brian Folkerts, C Jared Wheeler, G Derek Dennis, G Edmund Kugbila, G Andrew Norwell, G Chris Scott, T David Foucault, T Kevin Hughes, T Oscar Johnson, T Andrew McDonald, T Garry Williams.