HOUSTON - The worst part of the National Football League is the injury part, and the worst part of the worst part is when they bring out the cart to get an injured player off the field. You never get used to that, no matter how long you watch the sport.

Even when the moment is so obviously bathed in respect as it was when they came and got DeMeco Ryans yesterday, with players from both sidelines offering support as he was lifted onto the cart - old teammates from Houston, current teammates from Philadelphia, so many of them gathered - it is just wrenching if you allow yourself to dwell on it for too long. Because even as he showed no pain or emotion as he left, Ryans likely knew as he made the ride that his Achilles' tendon was torn, his season over.

The look on his face, the gesture of calm that he offered, a don't-worry-about-me kind of gesture, it all hit them a little differently. They all understood the implications both for the man and for them.

Mychal Kendricks is the protege.

"The way he exited the field - that's 'Meco, man," Kendricks said. "That's just the same guy. Every day, he's the same person. That just shows you, with adversity, he's the same person."

Bill Davis is the defensive coordinator.

"You just feel sick to your stomach for DeMeco because you know how hard he worked and what he's put into it and what he means to us," Davis said. "And the reason he means so much to everybody is because of how much he works and how much he's invested in this."

Chip Kelly is the coach.

"Everybody knows what DeMeco means to this team," Kelly said. And then he referenced "The Lion King," adding, "He's the true leader - we talk about it all the time. He's Mufasa. He's our guy. When a warrior goes down, you pick up his shield and go play in honor of him, and that's what I think our guys did."

Protege, coordinator, coach. They all need to make this work now. Everybody is going to spend the week talking about the quarterback after Nick Foles' injury, and understandably so. But how the defense does or does not rally in Ryans' absence is maybe even a bigger story.

Because, as everyone has heard over the last two seasons, Ryans is not only a linebacker who plays a ton of snaps and plays them more than credibly. He is not only the player who sets the defense whenever he is on the field. Ryans is also the leader, which can sometimes be an overrated concept but does not seem to be in this case.

Calm, stable, universally respected - it is a pretty unique package. And on a defense that can give up big plays with the best of them, a defense whose stability is often tested by those haymakers - as well as by the ridiculous number of turnovers committed by the Eagles' offense - Ryans' ability to keep his head amid the emotional swings is crucial. And now it is gone.

That presence is more difficult to replace than the player, and Davis admitted as much.

"He's a great player, but I would have to say the character, the intangibles, the culture part of DeMeco - I don't think you can replace it," Davis said. "He's that special. I think you can have other guys fill in to a certain degree, but his calming influence, his work ethic, all of those things, that's what you're missing."

Casey Matthews will play in some situations now, Davis said. Emmanuel Acho will play in some situations, too. But most eyes will be on Kendricks. He is the Eagles' ascendant young linebacker, a good player now and maybe a very, very good player in the future. Except that the future is for another conversation at another time. Now just became a lot more important.

"That's the game," Kendricks said. "We prepare for everything that happens in the game, but we don't know what's going to happen. Today, we had one of our soldiers go down. We're going to ride for him."

More questions followed. Kendricks stood in front of his locker and did his best to explain what happens from here. He cannot know for sure, of course. How could he?

"He's teaching me how to be a leader," the protege said, finally. "He's played this game a lot longer than me. I've been picking his brain ever since he got here and I'm going to continue to do that. That whole thing doesn't stop with him [being injured] - that's on and off the field. I'm going to keep learning from him."

He can only hope.

They can only hope.

Blog: philly.com/DNL