CLEVELAND — Before the game began, Darren Sproles executed a few sprightly, explosive drills. Nearby, Carson Wentz stretched a thick rubber band from one hand to the other and  behind his back, and pulled on it to warm up the throwing arm he would not use. At one point during a timeout in the game, left tackle Jason Peters, in cleats, uniform pants,  and a nylon undershirt, lumbered out to the field to advise his overmatched protege, Halapoulivaati Vaitai.

Within the next few years Peters will be enshrined 62 miles south of here. If he retires after this season, as Sproles plans to do, he might join Sproles at the summertime ceremony in Canton; that's how uniquely effective and productive Sproles has been in his 14-year career. Twenty years from now, with a couple of MVPs under his belt, Wentz might be joining their fraternity.

So it's of monumental consequence that none of these players took part in the 5-0 preseason loss to the Browns. Their absence contributed heartily to the "0" portion of the score. So did the absence of Alshon Jeffery, who led the team in touchdowns and led the receivers in yards but is recovering from shoulder surgery, and the absence of Nelson Agholor, who led the receivers with 62 catches but has a lower-body injury.

That's five key contributors absent from preseason action. Five players whose contributions likely would have helped the first-team offense avoid being shut out in the preseason.

Is this a harbinger of what the regular season will bring? Is there cause for the rising fear of a post-championship letdown? Is a bit of hysteria warranted?

We don't know. We can't know.

We know that Nick Foles, Wentz's backup, played poorly in his preseason chances. What we don't know is whether Foles will even play at all this season, because Wentz might return for the season opener Sept. 6 against the Falcons. He looks strong and mobile on his reconstructed left knee, and he's been taking snaps with the first-team offense for a week.

We know that Peters, the best lineman in team history, is immeasurably better than Vaitai at left tackle, and he'll be back from knee surgery in time to start the year. So will Sproles, who was averaging 4.1 yards per run and 10.4 yards per catch — his best per-catch average in seven seasons — when he blew out his knee in Game 3 last season.

We've been told that Agholor will be ready for the opener. Jeffery's presence is less assured.

But starting running back Jay Ajayi didn't play at Cleveland, either, and neither did his backup, Corey Clement. This is especially relevant considering the Eagles' rushing attack ranked third in the NFL in 2017.

How will the upgrade in personnel affect the product on the field?

We simply cannot tell.

Is what we've observed, and the impressions that were made, what the team really is? Should we be concerned?

Head coach Doug Pederson is concerned. Hopeful, but concerned.

"It'll be different. We just have to make sure these guys are ready to go in a couple of weeks," Pederson said after the Thursday night fiasco.

What if Wentz isn't medically cleared to play? What if Foles is one of those guys?

Pederson believes that the coaching staff can engineer game plans to hide Foles' weaknesses and accentuate the strengths of the team that made it the No. 3 scoring offense in football last year; innovative planning, daring play-calling, and a reliance on run-pass option plays.

"We're still pretty vanilla offensively. We haven't done any of our RPO game," Pederson said, referring to run-pass options. "Those are all things that are part of his strengths, too."

But Foles and the rest of the offense have been sufficiently stagnant that Pederson considered deviating from his plan and playing them in the second half against the Browns. Pederson wasn't going to call a bunch of RPOs in the second half. He just saw a unit that, though incomplete, was unacceptably imprecise.

At halftime Pederson told a sideline reporter he was very disappointed in Foles & Co., and he made sure the players heard that message in the locker room.

"When you don't score, being an offensive guy, I'm not jovial in there. The offensive just didn't do enough. They understand it. I wanted to make sure they heard it from me," he said. "The season begins in the next couple of weeks."

Sure, the Eagles won a Super Bowl. That was six months ago. They have a boatload of talent that hasn't done anything since.

"We've still got to put in the hard work and preparation," Pederson said, with a sigh.

Pederson said he's not patting any of the players who have played this preseason on the back. Until we see Wentz, Peters, Jeffery, Agholor, Ajayi, and Clement produce, we shouldn't be patting anybody on the backs, either.