Eagles' patchwork line pales next to Cowboys'

Despite having arguably the best offensive line in the NFL last season, the Cowboys drafted two linemen and gambled on an undrafted rookie who was earmarked for the first round until his pregnant former girlfriend was killed in the days before draft this offseason.

The Eagles, meanwhile, did very little to address a unit that lost a collective 20 starts to injury last season.

Even after Todd Herremans was released and Evan Mathis stayed away from the start of the offseason program, Chip Kelly passed on an offensive lineman for the second straight draft and took his team out of the post-draft chase for La'El Collins, who was eventually not considered a suspect in the death of his ex-girlfriend.

Both teams enter Sunday's rematch with losing records, but the Cowboys' fall to 2-5 has been much different from the Eagles' 3-4 start. Dallas lost five in a row after Jordan Hicks sacked Tony Romo and broke the quarterback's collarbone, while the Eagles have underperformed for myriad reasons other than the loss of their quarterback.

But the Eagles' 1-3 start was primarily caused by the offensive line's struggles, particularly in run-blocking. The group rebounded over the next stretch as the Eagles won two of three, but Kelly's offseason general managing is placing the onus on the line with Jason Peters unlikely to play against Dallas.

The likely absence of the Pro Bowl left tackle and the imposing shadow cast by Cowboys defensive end Greg Hardy had the Eagles scrambling to reconfigure their line this past week.

Lane Johnson moved to left tackle, Matt Tobin returned to right guard after replacing the injured Peters against the Panthers two weeks ago, and Dennis Kelly took Johnson's spot at right tackle after a difficult night at right guard in Charlotte. Jason Kelce and Allen Barbre remained at center and left guard, respectively.

In other words, the Eagles' season could hinge on three career backups, a third-year lineman playing left tackle in the NFL for the first time against one of the league's best defenders, and a center that had probably the worst game of his career in the first meeting.

"The challenge is going out there and not getting a whole lot of time to practice it," Johnson said. "It's one week and I haven't done it in a long time. But I'm going to go out there and give it my best."

If that sounds dire, there is hope. The Cowboys are starting Matt Cassel at quarterback, after all. He beat the Eagles with the Vikings two years ago, but his chances against an improved defense are strengthened, again, by arguably the best offensive line in the NFL.

The Cowboys line isn't invincible, and the Eagles teed off on left guard Mackenzy Bernadeau in September. But Bernadeau and the regular he was filling in for - Ronald Leary - are no longer in the picture. Collins has seamlessly replaced them and has, in fact, been an upgrade.

Knock Jerry Jones and the Cowboys for some of their questionable acquisitions, most notably signing the woman-beating Hardy, but they've gotten at least one thing right and that's been strengthening their offensive line for the last five years.

They expended first-round picks on linemen in 2011 (left tackle Tyron Smith), 2013 (center Travis Frederick), and 2014 (right guard Zach Martin). That's three of their starting five, and each one justifiably made the Pro Bowl last year. They are playing at a similar level this year.

Right tackle Doug Free, a 2007 draft pick, and Collins round out the unit. Third-round rookie Chaz Green had offseason hip surgery and is on the physically unable to perform list, but he gives the Cowboys a developmental prospect with some pedigree. Seventh- round rookie Laurence Gibson was released.

The Eagles haven't drafted an offensive lineman since they took Johnson with the fourth overall pick in 2013. They gave Peters and Kelce contract extensions before the 2014 season, but they have invested little in any additions they have made since.

Andrew Gardner, who opened the season as the starting right guard before suffering a season-ending foot injury, is one of the few free agents to stick. Backup center David Molk is also on injured reserve with a biceps injury. Josh Andrews is a reserve.

They aren't linemen that project to be any more than backups. Chip Kelly, of course, has made starters out of backups. There is very little known about the recently acquired Tanner Hawkinson. Undrafted rookies Malcolm Bunche and Brett Boyko remain practice squad curiosities for the time being.

Kelly has almost made it a foregone conclusion that he will draft an offensive lineman in the first round next year.

Despite the struggles, there was marked improvement in the run game over the last three games. The Eagles averaged just 3.1 yards per rush in the first three games and 5.2 yards since. But Kelly has increasingly had to use two-tight-end sets to help his five linemen.

He had to do it because the offense is run-based, but the passing game has suffered with slot receiver Jordan Matthews on the field less. He's had problems hanging onto the football, but he still poses more of a threat than any of the other Eagles' outside receivers.

The Cowboys were without Hardy, rookie defensive end Randy Gregory, and middle linebacker Rolando McClain in the first game and still managed to hold the Eagles to just 7 yards on the ground.

Kelly has tinkered with his run plays to disguise some tendencies. Having tight ends Zach Ertz (pass) and Brent Celek (run) on the field at the same time has also made them less predictable. But the coach attributed the improvement strictly to fundamentals.

"We've blocked better. Simple," Kelly said last week. "We didn't block well at the beginning of the year. We're blocking better now."

Will he be able to say the same after Sunday night?

jmclane@phillynews.com

@Jeff_McLane