The Eagles were 5-1 in those six games.
The common denominator: Vick played behind healthy, cohesive starting offensive lines.
Nick Foles now has compiled passer ratings of at least 100 for four games in a row: 158.3, 149.3, 104.3 and 112. In doing so, he stole the starting job from Vick. The Eagles are 4-0 in those games.
Vick never has had four straight 100-plus passer ratings.
Vick never has played behind such a healthy, cohesive line.
"If the quarterback is comfortable, knows what he has up front, he knows what to expect," said veteran guard Todd Herremans, part of each of the aforementioned successes. "As long as they're comfortable, they're going to have a better passer rating."
All of this cohesion will be sorely tested Sunday, when the Lions visit. With all due respect to the balanced and steady Cardinals defense, beaten by the Eagles last Sunday, not since Kansas City's 3-4 attack have the Eagles faced a defense with the capacity to be as fearsome as the Lions'.
They rank among the middle of the pack in total yards and points surrendered, but they crush the rush (third) and they get off the field on third down (first). They use a wide-nine alignment the Eagles used to varying effect in 2011 and 2012.
They also present massive and aggressive personnel challenges: 6-4, 298-pound tackle Nick Fairley and 6-4, 307-pound outlaw Ndamukong Suh.
"I know our guys will be up to the challenge of blocking them," said offensive coordinator Pat Shurmur, hopefully.
"We are," said center Jason Kelce, when asked if he and his guards were looking forward to the weekend. "They're one of the best duos in the game. They get off the ball really well. We have to do some stuff to throw them off their game in terms of protection schemes. You don't want to make it as vanilla as it usually is."
Injuries and coaching changes kept recent Eagles' lines from reaching the level of competence they are playing with today. This 2013 line did not enjoy the finest first 8 weeks - again, understandable. Stability requires time.
The dismissal of Andy Reid and his staff meant a third line coach in 4 years for left tackle Jason Peters and Herremans and a new offensive scheme for all five linemen, including, of course, first-round right tackle Lane Johnson.
Only one of the four returning veterans, left guard Evan Mathis, was not coming off a major 2012 injury.
The lingering effects were obvious for Peters, who twice ruptured his right Achilles' tendon in that offseason, as well as Kelce, who tore ligaments in his right knee in Game 2, and right guard Herremans, who scrambled the bones in his right foot, dislocating one and fracturing another in Game 8.
"My right leg still isn't as strong as it used to be," Kelce said. "They tell me it won't be until after the second offseason after I hurt it."
"Yeah, you're off it for so long you lose the strength in your leg," Herremans said. "I know my right leg is not as strong as it used to be. But it's coming along. There were times in the first few weeks, I needed to bear down or push off it and I just didn't have it. I feel it's back to normal now."
It will take a little longer before playing right guard feels normal. He had played right and left tackle and left guard in the NFL before this season, but never right guard. When the Eagles drafted Johnson to play right tackle, with Mathis entrenched at left guard (Herremans' most productive position), Herremans, 31 in October, was asked to move to right guard.
The transition lasted much longer than the preseason.
"It's taken a lot longer than I expected it to," Herremans said. "Every day I'm still learning techniques and stuff."
He could expect no help from his right side, where, understandably, Johnson foundered.
"I don't know if people forget, he's very inexperienced as an offensive lineman," said Eagles coach Chip Kelly, referring to Johnson's switch from small-town and junior college quarterback to tight end and defensive end as a sophomore at Oklahoma, then to tackle as a junior. "He has only been on the offensive side of the ball at offensive line for a short amount of time."
Little things are not second nature for Johnson, Kelly said: "Just the intricacies: his sets, set lines, his angles of departure from the line of scrimmage; little teeny things: where his hand placement is, is he too far outside of his hand placement, is he getting his hands back outside. It's in the details."
Now, Kelly continued, "He knows exactly what he's supposed to do and who he's supposed to block, but now working the intricacies that come along with just experience is what you're seeing from him."
The schedule didn't help, either.
The Eagles played their first three games in 11 days, then traveled to mile-high Denver, where altitude always benefits the Broncos (and Nuggets, and Avalanche). Kelly's rapid-fire, machine gun offense - most taxing on 300-pound linemen - had the unit worn to a nub by October.
That early grind might turn out to be a blessing.
"I think so," Herremans said. "We were still getting stronger as we went through the first part of the season."
They will need all of their strength against the Lions' front four - especially Suh, who, when channeling his aggression, can be un-blockable.
Then again, Suh seldom totally channels that aggression. He has been fined $139,375 this season for three separate incidents, most recently a throat-slash gesture Nov. 24 against Tampa.
Is he a menace?
"I don't look at him that way," Herremans said. "I think he plays hard. Everybody who plays football loses their cool every once in a while. I don't think he's out there maliciously trying to hurt people."
"Is he dirty?" Kelce asked. "I think a lot of that gets overhyped. He certainly does have that reputation. I don't think so. Then again, I could play him and find out he's even dirtier than I thought he was."
Dirty or not, if the Birds block like they have been, Foles should make it five straight.
On Twitter: @inkstainedretch