They have some excuses - defensive coordinator changes, the wide nine - but the fact remains that the Eagles had the worst tackling defense over the last two seasons, according to statistical analysis by the Football Outsiders website.
Many of those missed tackles came in the secondary. The Eagles safeties, in particular, have been woeful in this regard, their whiffs magnified because they are the last line of defense. If a lineman misses a tackle, a linebacker is usually there to clean it up. If a safety strikes out, the result can be a home run.
"Open-field tackling - that's the hardest thing to do in football," Chung said. "It's you one-on-one in the middle of field. So you have to be reliable."
Chung, for the most part, has been a reliable tackler. In 2010, when he started 13 games for New England, he missed seven tackles. Injuries and a demotion cut into his starts in 2011 and '12, and his tackling wasn't as strong, but it was nowhere near Nate Allen and Kurt Coleman levels.
Football Outsiders ranked the worst tacklers in the NFL last season, and Allen (12 missed tackles) and Coleman (11) were among the bottom 12 - not to mention departed cornerback Dominque Rodgers-Cromartie (12) and linebacker Mychal Kendricks (11).
Based on the percentage of missed opportunities, Rodgers-Cromartie (20.7 percent), Allen (16.4), and departed cornerback Nnamdi Asomugha (13.8) were three of the 10 worst-tackling defensive backs in the league. Coleman (12.0) wasn't far behind.
The Eagles finished last in Football Outsiders' list of the worst tackling defenses. Although Rodgers-Cromartie and Asomugha were sent packing, some of the worst offenders remain.
Chip Kelly has made an effort to acquire sure tacklers in the secondary. Cornerback Cary Williams (2.7 missed tackles) ranked in a tie for third in the NFL among the best in the secondary. Safety Kenny Phillips, when healthy, is as consistent a tackler as there is in center field. Safety Earl Wolff and cornerback Jordan Poyer were drafted in the fifth and seventh rounds, respectively.
Phillips, of course, has to prove his knees are near 100 percent. He missed another practice on Thursday, choosing to rest his left knee. But Chung is already penciled in with the first team alongside Allen, who could be given another chance to start.
Allen and Coleman have said that having less run-gap responsibility - as they had the last two seasons behind the wide nine - in new coordinator Bill Davis' scheme could cut down on the missed tackles.
But at safety, as Chung said, "if you can't tackle, you can't play."
"You might not have a gap, but you have responsibility," said Chung, 25. "If something happens, you've got to be able to tackle him, whether it bounces outside, whether it shoots right up the middle. I just call it a 'feel play.' "
Chung had fallen out of favor with the Patriots by the middle of last season. Some thought he had lost his edge because he was in the last year of his contract. He seemed to imply that he was battling nagging injuries.
"Last year is last year," Chung said. "Right now, I'm good. I'm in shape. I'm faster. And I'm having fun."
Contact Jeff McLane at firstname.lastname@example.org. Follow on Twitter @Jeff_McLane.