PHILADELPHIA (973espn.com) - While too many throw out their backs reaching for explanations as to why the reigning Super Bowl champion Philadelphia Eagles have started their sequel at 4-5, the real story is much simpler than that.

In fact, Occam's razor -- the philosophical problem-solving principle that says the simplest solution tends to be the correct one -- is absolutely at play here.

The Eagles are just too banged up to compete at a high level in a league where the have-nots are not all that far away from the haves when it comes to a talent perspective.

The problem starts with the outlier of the 2017-18 Eagles' season when the team overcame injuries to Carson Wentz, Jordan Hicks, Jason Peters, Darren Sproles, and others to win the first Lombardi Trophy in franchise history.

The assumption, however, that was going to be the rule and not the exception is where the disconnect began to fuel.

A regression to the mean in similar circumstances was inevitable and things have arguably been even worse for Philadelphia this season due to the injuries manifesting themselves in a redundant fashion at certain positions, first at receiver and now in the secondary with the latest hit coming in the form of Ronald Darby's torn ACL against Dallas on Sunday night.

No one ever wants to ever lean on injuries as an excuse but the sigh coach Doug Pederson let loose moments after the 27-20 setback to the Cowboys spoke volumes.

"I think it can, but you've been around us enough to know that we're not going to let that be an excuse," Pederson said when asked if the injuries have impacted things. "It's the next-man-up mentality. Just got to make sure that the next guy is ready to go and prepared."

On Monday the coach was a bit more playful when volleying with reporters.

“Do you have any eligibility left?” Pederson joked when asked about his secondary which was missing its top three corners -- Darby, Jalen Mills (foot) and Sidney Jones (hamstring) -- as well as free safety Rodney McLeod (knee) by the time things ended against Dallas. “It is hard. It's hard because you're asking players that maybe don't get a lot of practice time during the week to come in and play. They are on the 'look' teams. Maybe they're giving work to the offense, whatever it is. Next thing you know, they are having to play."

Jones might be back in New Orleans this weekend and Mills might return soon after but Darby will be headed to injured reserve to join McLeod and others like running back Jay Ajayi, receivers Mike Wallace and Mack Hollins, tight end Richard Rodgers, as well as defensive end Derek Barnett.

So the only thing left to do is move forward is the best way possible.

“We’re all pros," All-Pro defensive tackle Fletcher Cox said. "At the end of the day, the next guy needs to step up. We’re all in the same meetings, we’re all in the same practices and we all participate in everything together. The ‘next man up’ shouldn’t be an excuse.”

That's a great rallying cry but a player like Cox is simply more talented than his current backups, options like the recently-signed T.Y. McGill and Treyvon Hester.

While the chasm may not be as large in others areas there is a reason starters are starters and the backups have their roles.

Injuries may not be an excuse but they're sure an explanation.

"We just have to continue to coach those guys up, just like we do everybody, and make sure that now, moving forward, that they are ready," Pederson said.

-John McMullen covers the Eagles and the NFL for 973espn.com. You can reach him at jmcmullen44@gmail.com or on Twitter @JFMcMullen