For the second consecutive season, the San Francisco 49ers are 1-2. The Philadelphia Eagles, meanwhile, are 3-0 for the first time in a decade.

The Niners have been outscored 52-3 in the second half; the Eagles have dropped 74 points on opponents after halftime.

Can the 49ers buck those trends? NFL Nation reporters Paul Gutierrez, who covers the 49ers, and Phil Sheridan, who covers the Eagles, break down the Week 4 matchup:

Paul Gutierrez: Last year, LeSean McCoy led the NFL in rushing. This year, albeit only three games in, Nick Foles has the most passing yards in the league. Have the Eagles changed their identity or is this just a byproduct of Chip Kelly’s offense?

Phil Sheridan: I guess the best way to say it is the Eagles have been forced to change their identity, and that was possible as a byproduct of Kelly’s offense. I can explain that. Kelly’s approach is to figure out what a defense is trying to do, or is good at, and gear his offense toward the areas where that defense is vulnerable. So if defenses are loading up to stop McCoy and the run game, as they have in the three games so far, then Kelly will make them pay by throwing the ball. Washington, especially, packed the box and played close to the line of scrimmage on Sunday. McCoy had no room, especially behind an injury-ravaged offensive line. But Foles was able to find plenty of open receivers behind that run-oriented defense. If the Niners go blitz-happy in an effort to slow down Foles and the receivers, Kelly will serve up an adult-sized portion of McCoy.

My first and most obvious question is, what the heck is going on with those Niners? Most people expected them to challenge Seattle to be the best team in the league, not flop around among the worst. In a nutshell, are they just a win away from being back on track, or do the problems run deeper?

NFL Nation: Week 4 Previews Our NFL Nation reporters break down the Week 4 schedule: • Green Bay at Chicago

• Buffalo at Houston

• Tennessee at Indianapolis

• N.Y. Giants at Washington

• Atlanta at Minnesota

• Detroit at N.Y. Jets

• Tampa Bay at Pittsburgh

• Jacksonville at San Diego

• Carolina at Baltimore • Miami at Oakland

• Philadelphia at San Francisco

• New Orleans at Dallas

• New England at Kansas City

Gutierrez: Your answer to what’s eating them is as good as any they’ve offered publicly. But to play sports sociologist, chew on this -- the team that leads the NFL in arrests the past three years is also leading the NFL in penalties through three games. Undisciplined much? They added weapons to an offense that was going to have to compensate for a beat-up defense that is missing three starters in its front seven and breaking in three new starters in the secondary. They are still trying to establish an identity on offense -- power-running outfit or spread offense? And while the national storyline is that Jim Harbaugh is losing the locker room, I’d offer up the notion that his team is actually taking on his wild-eyed persona on the sideline, complete with histrionics and antics whenever a penalty flag flies its way. And yet . . . yes, winning is the ultimate deodorant. And if they can pull it together Sunday and hand the Eagles their first loss of the season, that would go a long way toward righting the SS 49er.

It seemed like that physical game against Washington took its toll on the Eagles, especially the offense. What’s the latest on guys’ health this week?

Sheridan: It was physical. Foles took something like 15 hits in that game. He said he was a little more sore than usual, but nothing too serious. Carry that over to the other 52 men on the roster and the Eagles were definitely feeling it after this game. They were coming off a short week, too. At least they’ve had a full week to recover and prepare for the Niners. They will be without center Jason Kelce, who went down with a sports hernia. That makes three-fifths of their starting line out of commission, with right guard Todd Herremans sliding out to play right tackle. The players know they will be tested until they prove they can handle it. The Niners’ biggest challenge may be deciding which part of the line to attack. Only left tackle Jason Peters will be lined up where he belongs.

How are the Niners coping with the absence of Aldon Smith and the other defensive players who are missing? Do they have the firepower to slow down the Eagles’ explosive offense?

Gutierrez: Sure, they knew it would take more than one player to replicate the pass rush generated by Smith, who has 42 sacks in 43 career games, though he is serving a nine-game suspension. But Dan Skuta and Corey Lemonier have yet to record a sack, and as a team, the Niners have only four in three games, with three by Justin Smith and one by Ahmad Brooks. I get the sense the 49ers themselves are surprised with the lack of a pass rush. I asked Skuta this week how they could generate it, and he said it was simply a matter of executing and each player doing his respective job. So I asked if it was a matter of scheme or desire. Skuta again said execution. If the Niners have any designs on slowing the Eagles, especially in the second half, they are going to have to take advantage of a weakened offensive line.

As such, the 49ers are the only team in the NFL yet to score a TD in the second half, having been outscored by a combined 52-3 after halftime. The Eagles, though, have scored more than 70 points after halftime. Are the Philly coaches that adept at making halftime adjustments, or does the nature of the Eagles’ offense simply wear down defenses so much that such success is inevitable in the game’s final 30 minutes?

Sheridan: It’s probably a combination of those factors plus one more: The Eagles have been outscored 54-27 before halftime. And 21 of those points came against Washington Sunday. Those poor starts have created a crisis atmosphere in the second half, and that is something the Eagles very much want to improve upon. But it is true they have rebounded with strong second halves. That has a lot to do with Kelly’s staff being pretty smart about what’s going on and how to correct it. And it has something to do with the Eagles’ conditioning. They do everything at a higher tempo, and they really believe that takes a toll on opponents. It certainly has been true that the Eagles have looked sharper, stronger and just plain better in the fourth quarter of all three of their games.

Before Chip Kelly came to the NFL from the Pac-12, Jim Harbaugh made the jump from Stanford. Is there a feeling that Harbaugh will stick around or could he be looking for a chance to jump back to the college game?

Gutierrez: Depends upon whom you talk to and the day of the week. It is true Harbaugh still has a year remaining on his contract and talks have been tabled until after the end of this season. But there’s a reason the rumors of discord between the coach and front office won’t go away. And now the rumor mill is working the Ann Arbor angle, what with Michigan, Harbaugh’s alma mater, potentially looking for a coach this winter. Plus, put this one away for a while: Could you imagine Harbaugh taking his khakis up the Bay to Oakland? It was with the Raiders where Harbaugh cut his NFL coaching teeth, after all.