Eagles defense has a hard time stopping the run

They are the last line of defense, but let's start with the safeties and what went wrong when Jordan Todman raced 63 yards through the Eagles defense for a touchdown Saturday night in Jacksonville.

After the Jaguars running back cut back against the leftward push of his offensive line and the Eagles linebackers were taken out, Patrick Chung was the first safety to come up and help. Chung lined up to the left before the snap, just outside the hash marks, so he had a ways to go.

But he should have been able to stop Todman. Instead, Chung overpursued the play and was upended by Jaguars tight end Allen Reisner. That left Earl Wolff as the lone safety (valve).

The rookie, who was working with the starting defense for the first time, came up from center field but took a bad line to the speedy tailback. Todman simply angled outside and Wolff tackled only air.

"I was being too aggressive. Took a bad angle," Wolff said after the game. "I'm not one to take a bad angle, but it happened. I'm going to learn from my mistakes."

Wolff and Chung weren't the only Eagles defenders to make mistakes against the run this preseason. Opposing offenses have averaged 174.7 yards a game and 5.8 yards a carry through three games.

Todman's run and a 62-yard dash by Patriots running back Stevan Ridley accounted for a significant number of yards, but there were also several 8-, 9-, and 10-yard gains that suggested more was at play than just a few breakdowns.

The main issue appears to be gap responsibility. The Eagles are moving from a 4-3 defense to a two-gap 3-4 (they hope). Several players are learning new positions or different takes on old positions, so the transformation will take time. It's still only the preseason.

After the Patriots ran the Eagles through the Veg-o-Matic, the first-team defense showed some improvement in the second exhibition game against the Panthers. But it regressed against a Jaguars team that many believe could be picking No. 1 in the 2014 draft.

"I think we've done a better job overall of getting people to run to the ball," Eagles coach Chip Kelly said. "We're gang-tackling better as a group than we did in the first game."

That's a gentle way of putting it. The issues on run defense are threefold: up front, at linebacker, and in the secondary. The Eagles have competent-to-above-average run stoppers at each spot, but there are weak links, and when one of the more talented players fails in containment, a long run is always possible.

The defense had the same problems the last two years, although the issues were partly because the Eagles did not have the right fits for the wrong scheme. There are still some missing pieces, but they spent considerably on adding heft up front.

Isaac Sopoaga was acquired in free agency and Bennie Logan was taken in the third round of the draft. They have split most of the repetitions at nose tackle. The 31-year-old Sopoaga was a solid anchor for years in San Francisco, but he's on the back end of his career. Logan has flashed promise, but the Eagles don't want to overextend the rookie.

They got little push against the Jaguars. Defensive ends Fletcher Cox and Cedric Thornton will be fine. But they often will be asked to eat up blockers as two-gappers and free up linebackers to stop the run.

Right now, that's where the most pressing problems lie. DeMeco Ryans was far and away the Eagles' best run-stopping defender last season. But he was alone in the middle and now he's inside with Mychal Kendricks.

Ryans has not played well this preseason. It's a little too early to panic, especially since he was equally as bad last preseason. But Ryans' return to a 3-4 bears watching since it wasn't the best fit for him in Houston.

Kendricks has been all over the field the last two games. He has a nose for the ball and is fast enough to cover and rush the passer. But his specialty isn't taking on offensive linemen at the point of attack. He often has trouble disengaging from blocks.

If Ryans and Kendricks can't get free, the Eagles safeties will need to help. Chung has been solid against the run. The Todman touchdown was an isolated incident. But Wolff can't possibly be expected to start right away, and Nate Allen isn't strong in run support.

Veteran Kenny Phillips was supposed to challenge Allen for the job, but he couldn't get healthy and was released on Sunday. Kurt Coleman, Colt Anderson, and David Sims are at the bottom of the barrel.

There is a safety net: The Eagles may be able to scrape up a replacement once teams trim their rosters to 53 on Saturday.