Foles started for the second consecutive game due to an injury to first-choice quarterback Michael Vick but failed to replicate his impressive performance from last week, finishing with 11 of 29 for 80 yards as well as being sacked three times.
However, Kelly believes that the whole of the offense should take responsibility for only getting three points on the board, despite Foles missing a number of throws to open receivers, including one to Jason Avant in the end zone.
"All of us on offense, our decision making wasn't very good. It was all of us on offense. It's not just one guy," Kelly told The AP.
Foles was replaced by Matt Barkley in the final quarter, but the debutant did not fare any better, throwing three interceptions in what he regarded as a learning curve.
"I was maybe a little too aggressive on some of those throws, trying to advance the ball down the field and help our team win. I learned a lot today. I'll learn even more watching the tape," Barkley added.
The result leaves the Eagles trailing the Cowboys at the top of the NFC East.