ATLANTA -- Jim Schwartz was standing on the sideline with his hands on his hips, gazing out on a football field in transition. Maybe he was looking at the video screen, or at the referees, or maybe he was just staring into the middle distance, pondering the cruelty of his existence. Whatever the case, he was not looking at Ronald Darby.

As the veteran cornerback walked past his defensive coordinator in the wake of a 4-yard touchdown pass to Julio Jones, the two men barely seemed to acknowledge each other’s existence. Darby shook his head. Schwartz yelled a few words at the officials. And then the two men settled into their respective patches of the sideline, where they contemplated a question that did not appear to have an answer.

Among all of unfortunate developments that the Eagles somehow endured in their 24-20 loss to the Falcons on Sunday night, the further muddling of their secondary might be the one that most seriously impedes their Super Bowl hopes. This is assuming, of course, that Carson Wentz is the quarterback we saw after his brief retreat to the sideline late in the first half: that his head his OK and his ribs are not currently in the form of puzzle pieces, that he can continue to do the things we saw him do while marching the Eagles down the field for a couple of touchdown drives that gave them their most improbable lead in quite some time. It is also assuming that all of the other bodies that followed an interminable march into and out of the blue medical tent will return before long.

Granted, that’s a lot of assumptions. But, given them all, the lasting worry about this Eagles team remains a secondary that, through two weeks, has too often looked like it is running at three-quarters speed. With Darby, that’s of particular concern, because speed is his game. Even before that third quarter play where he allowed Jones to outmaneuver him and position himself for a 4-yard touchdown catch off a Ryan scramble, Darby had been roasted by second-year Falcons wideout Calvin Ridley on a 34-yard touchdown and only narrowly escaped a similar fate at the hands of Justin Hardy (Ryan overthrew the Falcons backup, who had a couple of steps on Darby deep). Not since Byron Maxwell had Eagles fans witnessed a performance so singular in its egregiousness.

“There’s no excuses,” Darby said. “I just made a few mistakes. Come back better next week. Make some plays. At the end of the day, this game’s in the past. I made some plays that hurt us, but I’m going to come back stronger."

There’s a thin line between excuses and legitimate explanations, and it certainly appeared as if Darby might have one of the latter in the form of his surgically reconstructed knee that ended his 2018 season early. Asked several times whether he felt like he was fully the player he was before the injury, Darby repeated the no excuses mantra. Take that however you like it, but it seems like a reasonable assumption that, on Sunday night, we saw a player who still has not completely regained his sea legs after an offseason of rehab.

“I’m good,” Darby said. “Ain’t no excuses. At the end of the day, if I didn’t feel like I wasn’t good enough I wouldn’t be out there. I just have to keep working, keep getting right, and come back stronger next week.”

One thing we can say with certainty: the Eagles need Darby at 100 percent. He might not be an elite shutdown corner, but he has levels of experience and foot speed that are lacking on the other side of the field, where Sidney Jones replaced Rasul Douglas in the starting lineup in the wake of a rough Week 1 showing against the Redskins. With road games against the Packers, Vikings and Cowboys looming in the next five weeks, the Eagles are in the midst of what they could look back on as a defining stretch of their schedule. They showed on Sunday night that they can whether even the most trying of circumstances, with Wentz turning in a gritty second half performance that one teammate suggested was the best of his career. At some point, though, they are going to need to be able to keep pace with receivers like Stefon Diggs, and Amari Cooper, and Michael Gallup, and Davante Adams.

You can easily argue that the presence of the pre-injury Darby was the only thing standing in the way of the Eagles and a 2-0 start. That’s not a death sentence, mind you. One of the hallmarks of this defense under the stewardship of Schwartz has been its ability to grow and evolve over the course of a season. Things weren’t pretty last season either, and the Eagles still very nearly ended up in their second straight NFC championship game.

At the same time, rarely has it been as ugly as it was for Darby last night, or for Jones and Douglas in their combined attempt to keep pace with Redskins rookie speedster Terry McLaurin last week. The NFC features plenty of receivers who are bigger, faster, stronger and/or more technically skilled than Ridley, Hardy and McLaurin. At some point, the Eagles are going to need to rely on something other than errant throws to stop them.

That’s the only thing that stopped the Falcons on Sunday. Ryan completed 27-of-43 passes for 320 yards and three touchdowns and three interceptions, one of which came in the end zone. Jones and Ridley both went over 100 yards. Two weeks into the season, three receivers have reached the century mark.

It was a wild one in Atlanta. And, for Darby, one that he can only hope will become less frequent with time.