"It's the key to playing any position or doing anything you do," Foles said. "You want consistency. You don't want a drastically bad day and then a great day. You fluctuate too much. That's what we always strive for is to be consistent. And a lot of that has to do with preparation."
Neither Foles nor Kelly would broach what will happen when Vick returns from a hamstring strain. But Foles has shown that he can effectively run Kelly's offense. One of the keys is how he distributes the ball to so many targets.
In the seven-touchdown game, Foles threw touchdown passes to five players. DeSean Jackson and Riley Cooper both eclipsed 100 yards. Jackson and Cooper also caught touchdown passes during Foles' win over the Tampa Bay Buccaneers on Oct. 13.
Cooper has benefited the most from Foles' entry into the lineup. He has 12 catches for 291 yards and four touchdowns with Foles behind center, and eight catches for 93 yards and one touchdown playing with Vick. Vick has attempted 23 more passes than Foles this season.
Foles seems to trust that Cooper can get open even when he appears covered. Foles insisted he does not try to get the ball to certain players and simply goes based on what he sees from the defense.
"I never go into a game saying I'm going to give this guy five balls," Foles said.
Tight ends Brent Celek and Zach Ertz also combined to have productive games with Foles at quarterback, although that was the product of the Eagles' playing more two-tight-end sets. They did so because Kelly thought the bigger offensive package would work against the defensive formations the Raiders were using.
It was one way of getting more playing time for Ertz, the talented second-round draft pick. Ertz's five catches Sunday were his most of the season, and he scored his first career touchdown.
Kelly, however, continued to insist that the two-tight-end set would be featured depending on the matchup. He will not use it just to put Ertz on the field, he said.
"We're not calling plays saying, 'Let's get the ball to here.' You've got to have weapons at every position," Kelly said. "I think in this league people are good enough to take one guy away. . . . What we've always tried to do is make sure you cover everybody."
Kelly pointed to the way teams have leaned toward Jackson, which theoretically allows Cooper to take advantage of single coverage. And if defenses focus on the wide receivers, Kelly said, the tight ends are capable of big games.
"What we're really striving for is balance," Kelly said. "We're not trying to individually force the ball to one guy. I think we have the weapons at all different spots, whether at running back, wide receiver, tight end, to take care of that stuff."
Foles has achieved that balance when he has played well this season. The problem is the Cowboys game, when he played poorly.
That's why Sunday's game is so important for Foles. If he can continue distributing the ball and avoiding turnovers - Foles does not have an interception this season - he could force Kelly's hand.
It's not my choice," Foles said. "I'm just excited to play."
Seven touchdowns in one game seemed convincing enough. When Foles was asked how many touchdowns he must throw to persuade Kelly to start him, even Foles cracked a smile.
"I trust Chip with everything," he said. "No matter what, I go with him."