WE ARE about to find out just how good Chip Kelly really is. We are about to find out if he can find a way to win without his most valuable offensive weapon.

No, nothing has happened to LeSean McCoy or Nick Foles or Jason Peters. While all of them obviously are important cogs in the offense, none of them is as irreplaceable as Jason Kelce.

Kelce had surgery Tuesday to repair a sports hernia. Depending on just how serious the damage, he figures to miss between five and seven games.

The 26-year-old center is the straw that stirs the Eagles' offensive drink. His unique athleticism, his speed, his ability to make the rapid line calls that are required in Kelly's faster-faster-faster tempo offense, make him worth every penny of the 6-year, $37.5 million contract extension he signed during the offseason.

And now he's gone until probably mid-November, and we'll see how that goes.

"Jason is the best center in football," said NFL Network analyst Brian Baldinger, who spent more than a decade as an offensive lineman in the league. "It's hard to replace a guy that valuable. There's no getting around it. Their line isn't going to be nearly as good without him."

At a big-time college program like Oregon, where Kelly was last employed, depth, even with NCAA scholarship restrictions, is a bottomless pit. You lose a good player, there's usually another good one in the weight room to take his place.

That's not necessarily the case in the NFL, where the salary cap makes it difficult to stockpile talent.

Kelce's replacement is 6-foot, 290-pound David Molk, who was signed as a street free agent last January after spending the 2013 season back home in Illinois helping coach his old high school team. Sunday's game against the 49ers will be his first career start.

"Losing your center is very difficult to overcome," said Mike Mayock, an analyst for NFL Network and NBC. "In today's NFL, the center is as important as the left tackle. They make the calls. In the Eagles' offense, in addition to [calling] the pass protections, he's also a key guy in their zone run game. He's got combination blocks both right and left. It's about timing and knowing when to separate. There's just so much of it.

"So they're losing a guy who's probably the most athletic center in football. It's going to hurt them in the run game. It's going to hurt them in the pass game and in pass protection. Nick Foles is going to lose a guy he trusts. In all levels, in all phases, it's going to hurt the Eagles."

Foles said yesterday that he has complete faith in Molk. Then again, would you really expect him to say anything else?

"The offense does fit him," Mayock said of Molk. "He's a little bit of an undersized, quick scrapper. He's really, really smart. So he has traits you can win with.

"I think when you get [suspended right tackle Lane] Johnson back [next week] and this kid gets some more reps, it will help. I guess the question is, as they get people back, does it make up for the fact that they've lost an All-Pro center?"

There isn't another center in the league as athletic as Kelce. Watching him sprint to the perimeter after snapping the ball to lead the way for McCoy or Darren Sproles on an outside zone run or screen is worth the price of admission. People still are talking about that play in the second quarter Sunday when he was running stride for stride downfield with Redskins safety Ryan Clark on that 50-yard bubble screen to Jeremy Maclin.

"There's nobody his size that can run like that in this whole league," Baldinger said. "So much of what they do relies on athleticism. When you've got Kelce and Johnson and Peters out there, they just look like a bunch of deer out there. All of them can run, and run really well. Whether it's getting to the back side or cutting guys off or leading screens, he's so great at that part.

"At the same time, you watch him in the preseason against [Patriots defensive tackle Vince] Wilfork or even [Redskins nose tackle Chris] Baker on Sunday, his hands are so good. He has the ability to wheel guys. Even on the play he got hurt on, he was taking Baker for a ride down the line of scrimmage. He had him on skates. It's going to be a really tough loss to overcome."

Molk, who played at the University of Michigan, was selected by San Diego in the seventh round of the 2012 draft. He's athletic and can run, but he isn't nearly as adept as Kelce at getting leverage on bigger players. He struggled with the 350-plus-pound Baker after replacing Kelce early in the third quarter.

"I thought the kid competed," Mayock said. "To me, you're losing an All-Pro center and you're getting a kid that is smart, tough, quick and will compete."

Said Baldinger: "The one thing Molk can do is he can run. He can't run quite like Jason. Nobody else can. I've always said that those blocks on the perimeter on some of those outside zones and screens and things like that are as important as any interior blocks.

"Molk can't do a lot of that stuff. Baker really exposed his lack of size and strength. He's a nice little gutty player. He's smart. His snaps are good. He can run, but he can't do what Jason can do."

Figuring the Eagles

* After three games last year, LeSean McCoy led the league in rushing with 395 yards and was averaging 6.4 yards per carry. After three games this year, he's 17th with 175 yards - 210 yards behind the Cowboys' DeMarco Murray - and is averaging 2.9 yards per carry.

* In their first three games, the Eagles have used three-wide receiver sets on just 127 of their 215 offensive plays (59.1 percent). Last year, they used three wides 72.3 percent of the time. Nick Foles has completed just 56.6 percent of his passes (47-for-83), is averaging 6.3 yards per attempt and has an 81.7 passer rating with three wide receivers on the field. He had a 58.2 rating out of that formation in the first two games, but it jumped 23 1/2 points Sunday when he had a big day out of three-wide receiver sets against the Redskins, completing 23 of 34 passes for 226 yards and three touchdowns.

* The Redskins converted eight of 15 third-down opportunities against the Eagles, including seven of nine in the first half. Ten of those 15 third-down situations were three yards or less, including eight of nine in the first half. A breakdown of opponent third downs in the first three games:

 
3rd & 3 3rd & 7
Opponent No. or less or less
Redskins 15 10 4
Colts 12 3 5
Jaguars 14 3 10

* The reason for the plethora of third-and-shorts last week was because the defense wasn't playing very well on first and second down. Two hundred ninety-eight of the Redskins' 511 total yards came on first down. The 'Skins averaged 8.3 yards per first-down play against the Eagles. DeSean Jackson's 81-yard touchdown catch, Pierre Garcon's 43-yard reception against Cary Williams and Nate Allen that set up Kai Forbath's failed 33-yard field goal attempt, and the 55-yard screen pass to Roy Helu all came on first-down plays. So did Malcolm Jenkins' big interception. Redskins quarterback Kirk Cousins was 12-for-18 for 248 yards and two touchdowns on first down. In the Eagles' first two games, the Colts and Jaguars averaged just 4.2 yards on first down. Quarterbacks Chad Henne and Andrew Luck were a combined 12-for-25 for 158 yards and no TDs on first down.

* Just one of the Eagles' nine touchdown drives has been fewer than five plays. Last year, 22 of their 51 TD drives were four plays or less, including five in the first three games.

* The Eagles' longest touchdown drive timewise has been 3:16. Of their 39 possessions in the first three games, just five have eaten up more than 3:30.

* Bill Davis has sent five or more rushers after the quarterback on 49 of 128 pass plays (38.3 percent) in the first three games. A breakdown of their pass rush and the results:

  Plays C-A Yds. TD/I Sk.
Rush 3 7 6-7 56 0/0 0
Rush 4 43 22-42 228 2/1 1
Rush 5 18 9-17 102 2/0 1
Rush 6 11 7-10 52 1/0 1
Rush 7 1 0-1 0 0/0 0

* The average opponent drive start in the Eagles' first three games has been the 25.1 yard-line. Twenty-six of their opponents' 41 possessions have started at no better than their own 20-yard line. Kicker Cody Parkey has played a big role in that. Fourteen of his 21 kickoffs have resulted in touchbacks. Just seven of their opponents' drives have started at the opponents' 40-yard line or better.

* The Eagles have a plus-26 fourth-quarter point differential through the first three games. That's the second best in the NFL behind only the Cardinals' plus-30. The Cardinals have not allowed a point in the fourth quarter this season.

THIS AND THAT

- It's uncertain exactly when Jason Kelce will be back.

Dr. William Meyers, who did the surgery to repair the center's sports hernia, has said that he's had patients come back in 3 to 6 weeks.

"I would think that's probably a reasonable time," said Dr. Arthur Bartolozzi, who is director of sports medicine for Aria 3B Orthopaedic Institute. "But I would go with a longer [return] than a shorter [one]. That gives the player some time to fully recover, feel comfortable and get back to the ability to perform ballistic activities."

Dr. Ulrike Musthaweck, a German surgeon, has performed a less invasives ports hernia surgery on dozens of professional soccer players over the last decade and has had them back on the field in as little as a week to 10 days. Justin Shaginaw, who is the lead therapist/coordinator of sports medicine at Aria 3B and served as an athletic trainer for the U.S. World Cup team, said Michael Owen, a former player for England, had sports hernia surgery done by Musthaweck a week or 2 before the 2006 World Cup and returned in time to play.

"There was another player who had it done about 3 weeks before the 2010 World Cup," Shaginaw said. "There is less trauma with her surgery. So, in theory, players can come back a little sooner than they can with Dr. Meyers."

Many MLS players with sports hernia injuries have flown to Europe and had them repaired by Musthaweck. NFL players have yet to follow suit.

- Bill Davis has no idea why his defense is struggling so much in the first half. In the Eagles' first three games, they've given up 54 points in the first half to just 24 in the second half. Opponents have converted 10 of 22 third-down opportunities in the first half and just four of 19 in the second half. Opposing quarterbacks have a 123.1 passer rating in the first half and 69.8 in the second. "We've got to find a way to start faster and play tighter coverage early, stop the run and get that third down to where it's more manageable, like it was in the second half last week," Davis said.

- Eagles running back Chris Polk, who returned a kickoff 102 yards for a touchdown against the Redskins last week, said the hamstring injury that sidelined him for the entire preseason and Week 1 still hasn't completely healed. "It still isn't 100 percent," he said. "But it's good enough to where I can play and get through games and do the stuff I like to do. But as far as being 100 percent, I'm not there yet." Polk has four touchdowns in just 19 career touches with the Eagles.

2-MINUTE DRILL

FROM THE LIP

"I think his moral sway has absolutely evaporated. He's a ghost now. I don't know when he'll leave, but I don't think he can continue to have any kind of real credibility. I think what the league needs is somebody from the outside. Remember, Goodell grew up in the league. He's a lifer. He only sees it from a football point of view." - NPR sports commentator Frank Deford, on commissioner Roger Goodell

"I won't change my statement that this is Robert's team. I still stand by that. He was drafted high for a reason. He's had success here. He's done a lot of good things. He's done nothing to have that be any different." - Redskins QB Kirk Cousins, on Robert Griffin III

"They're trying to build cohesiveness. That's what they're trying to do. It's not an easy thing to do. But it will happen if they're patient. They're trying to get guys in the right spots. To do that, it does take time."- Recently retired Patriots offensive line coach Dante Scarnecchia, on the team's problems protecting QB Tom Brady

"Cary doesn't say [I'm] sorry too much. I think [his comments] were off emotion. Who knows what he might've been dealing with. It's one of those things where we need to keep our communication in-house."- Eagles linebacker Brandon Graham, on Cary Williams' apology to the team for critical comments about Chip Kelly's training and practice methods

BY THE NUMBERS

- Since 2002, the Eagles have had 89 games in which they haven't thrown an interception. That's the third most in the league, behind only the Patriots (101) and Jaguars (93).

- With last week's 16-9 win over the Raiders, the Patriots have won 31 consecutive home games against conference opponents. That's the longest streak since the AFL-NFL merger in 1970.

- Cowboys running back DeMarco Murray has rushed for 100-plus yards and scored a touchdown in each of his team's first three games. He is the first player to do that in three consecutive games since the Jets' Curtis Martin in 2004.

- The 49ers have been outscored, 52-3, in the second half this season. iThe league passer rating through the first 3 weeks is 90.6. That's the highest ever in the first 3 weeks of a season. The highest league passer rating for a season is 86.0. That was last year.

- The league's interception percentage (2.15) also is the best ever for the first 3  weeks of a season. The previous best was 2.55, also last year.


On Twitter: @Pdomo