By his own admission, McCoy had a pedestrian game Sunday - "one of my worst performances since being a rookie," he said afterward. He rushed for 55 yards on 18 carries, and there were occasions that he cut and faked so many times during a single run that he seemed to moonwalk himself into the waiting arms of a Dallas defender. But his least productive game this season, actually, was on Oct. 6 against the Giants - the day Vick injured his hamstring - when he mustered just 46 yards on 20 attempts.
It was natural to think that McCoy found so little room to run against the Giants because the success of Kelly's iteration of the read-option depends in large part on a mobile quarterback. Once Vick left the game and Foles replaced him, the reasoning went, the Giants no longer had to honor the possibility that the Eagles' quarterback might feign a handoff to McCoy and carry the football himself.
The Eagles' convincing victory the following week against Tampa Bay, when McCoy rushed for 116 yards even with Foles playing the entire game, put the lie to that notion, at least temporarily. The Eagles have to hope they can repeat or approximate that performance against a Giants defense that entering Monday night was 15th-best in the NFL against the run, giving up an average of 3.9 yards per attempt.
Kelly insisted Monday (rather conveniently, one might add, considering that he calls the plays) that the Eagles' rush-offense schemes weren't the problem against the Cowboys.
"There were a lot of times when the numbers were right for us," he said. "We do have a hat for hat. We've got to finish it. There were other times when maybe the ball should have gone outside because of how we're blocking it and what the landmarks are, but the back cuts it inside. We've just got to get everybody on the same page."
If that's true, if all that's required for the Eagles to run the ball effectively is better blocking and better decision-making by McCoy, then Kelly should have no hesitation about leaning on McCoy more. He really has no other choice.
Unless Foles' concussion is so mild that he sails through the league's protocol for head injuries and is cleared to play, Sunday's starter will be a hobbled Vick or a healthy Barkley. Either way, McCoy's importance to the offense should only increase, if it's possible for it to increase.
We'll see just how much. With Kelly, so much is still so new. For the 14 years that Andy Reid was the Eagles' head coach and the 61/2 seasons that Marty Mornhinweg was their offensive coordinator, it grew easier to sense how the two of them would react and respond whenever the starting quarterback position became the least bit volatile.
In 2003, when Donovan McNabb was struggling with an injured thumb, Reid created the "three-headed monster" with running backs Duce Staley, Brian Westbrook, and Correll Buckhalter. If McNabb or Vick was in the midst of an erratic game or a midseason slump, Mornhinweg was inclined to continue calling passes, reasoning that a quarterback of McNabb's or Vick's quality deserved as many opportunities as possible to rescue his team with a spectacular play.
"Depends on who it is. Depends on what's going on," he said.
On to Sunday, then, where we'll all learn a little more from a game that should be LeSean McCoy's to win.