As innovative as head coach Chip Kelly's supporters claim he is, there are fundamental elements of the game that always ring true.
Friday night's 34-28 loss to the Chicago Bears showcased once again the importance of protecting the football. The Eagles had four turnovers - three interceptions and a fumble - which is a recipe for trouble.
"We turned the ball over too many times on the offensive side of the football if you're going to win football games. That part of the game doesn't change," Kelly said. "I think they're aware that if you play the turnover game in this league and if you're on the negative side, you come out on the negative side in the game.
"We've got to be smarter with the football."
Quarterback Nick Foles had two interceptions, but Kelly was able to put the preseason opener in its proper context.
"It's one preseason game. He got X amount of snaps. We'll make corrections and go from there," Kelly said.
Meanwhile, backup quarterback Mark Sanchez led the Eagles on two touchdown drives.
"I was real impressed with the work he did in the second quarter. I thought he threw the ball on time. He put the ball in there," Kelly said. "He made a mistake on the one play on the goal line where he tried to pull it and throw it out. We were on the 1-yard line but we got (the touchdown) on the next play, so it didn't come back to hurt us."
Sanchez developed a rapport in Training Camp with rookie wide receiver Jordan Matthews, who had four receptions but struggled with some drops.
"I thought he was just inconsistent," Kelly said. "There was that ball on the sideline he could have caught. I don't know if he was pressing or whatever."
Fellow rookie Josh Huff made the highlight reel with a 102-yard kickoff return for a touchdown to cap off a 21-point second quarter for the Eagles.
"The one thing he can do is he can finish. He's a big, strong guy. He did a great job stiff-arming the kicker in finishing," Kelly said. "Josh has that mentality where he'll hit and come out the other side and when you come out the other side, you've got to make the kicker miss. It was a real physical move by him then he's obviously got the speed to finish."
On defense, Kelly was encouraged by the depth along the line of scrimmage.
"I thought Beau Allen was a disruptive force in there," Kelly said. "I thought Brandon Bair, it seemed like he was flying around, involved in a lot of plays."
Kelly wants to see the pass coverage tighten after tight end Zach Miller victimized the defense for a pair of touchdowns.
"They scored twice on the same throw to the same guy on the same pattern," Kelly said. "They threw back-shoulder throws with the linebacker covering him. We're close in coverage, but we're not close enough."