You all know which play I mean: first and goal from the Arizona 6, right after Riley Cooper's spectacular one-handed catch and spin move. Those who were wondering what trickeration Chip Kelly might have cooked up over bye week found out.

Recent pickup Brad Smith came in as quarterback in the shotgun, with Shady on his left, a gassed Cooper sideline left, Avant slot left, and Nick Foles lined up sideline right as a wide receiver.

Unfortunately, Smith whiffed on the snap, which bounced off his chest and hit the ground. He picked it up at the 11 yard line and got to the ten, running left, before he was brought down. 4 yard loss. After a two yard run by McCoy and a sack of Foles, the Eagles kicked a field goal.

A chorus of criticism followed, from generally intelligent Eagles beat writers who unanimously called this a "wildcat" play, to Ashley Fox's infamous 1,500 word rant, which I won't even dignify with a link. Most missed the basic point: Chip didn't call a fumble. And he did not call a wildcat run.

That leaves an interesting question: what would the play have been, if properly executed? And was it good idea?

A wildcat, by definition, means hiking directly to a running back so you can replace the quarterback with another blocker. (LeSean McCoy ran it a lot in college, at Pitt; if he took the snap, it would be a wildcat.) Brad Smith has played every skill position; in 8 years, he has caught 101 passes for 949 yards, run 133 times for 970 yards, and passed on 9 snaps for 57 yards and 1 of his 15 TDs. A quarterback can't run the Wildcat by definition; if he runs, it's just a quarterback keeper.

It's also not at all clear that Smith was planning to run. LeSean came by for a possible handoff or fake, moving right with a lot of open field in front of him, and Smith had 3 receivers facing single coverage. As the play fell apart, Cooper was throwing a move on CB Jerraud Powers, Avant was running a crossing route at Honey Badger along the goal line, and CB Patrick Peterson was on an island with Foles. The handoff to Shady and cross to Avant look most likely, and both had a strong chance of success. If Smith was going to run, he ought to have followed Shady to the right, but Bryce Brown or James Casey would have made more sense as a lead blocker.

Look at the matchups this formation created: 6'3" Riley Cooper one on one against the Cardinals' weakest back, 5'10 Jerraud Power, with the whole left side of the end zone to play in, and wily veteran Jason Avant facing a rookie safety whose attention was split with stopping the run. Best of all, the Cardinals best CB, Peterson, was isolated on Nick Foles at the far sideline. That doesn't make much sense for Arizona, but there was no time to rearrange.

A surprise play pops up, and suddenly there's a 6'6" WR split far right. WTF? Who's number 9? Oh, it's just Foles. Peterson couldn't run across field and point to Powers, yelling "SWITCH! SWITCH!" He couldn't simply ignore Foles, either; I haven't seen Nick catch a pass, but he's a former basketball player who takes 90% of his snaps in the shotgun. I'm pretty sure he could pull in a wide open floater.

There's also the possibility of a stunt: Smith tossing backwards to Foles (as the Eagles have done twice in recent games) so that Nick could throw to a receiver who has come open (perhaps Shady, or Brad Smith himself.)

Chip Kelly enjoys the occasional crazy play to keep defenses guessing, but they are always based on fundamental football. In the failed two-point conversion against Kansas City, Philadelphia had favorable numbers; Ertz was caught from behind by Tamba Hali, who rookie tackle Lane Johnson left unblocked. Oops.

So was this play a good idea? I think so, and some smart people like Tommy Lawlor agree with me, though Chip is probably right that every play that fails is "stupid" and every one that works is smart. (I doubt anyone would have criticized Chip if he ran LeSean into the pile for a 2 yard loss, though.)

Critics need to remember that this was one play, on first down. The Eagles only got two yards on Shady's second-down run, and then Foles was sacked. Arizona is simply a good defensive team, and one failed play didn't permanently cripple the Eagles' offense.

This play does point to a fundamental paradox in Kelly's programs. He is deeply committed to players running plays they know well, through countless repetitions in practice and in games. At the same time, it helps to surprise opponents, and surprise will always be greater with plays you've run less. Bye week is the best time to finesse this dilemma, as you have more time to practice something in secret. Clearly they didn't have enough reps to get it down, though in general I'd trust a versatile veteran like Brad Smith in this kind of situation.

One question is, why not use Michael Vick at QB with Foles on the wing? Well, there would be less surprise; Vick has known tendencies that opponents can work against. Smith is also taller, at 6'2". Mostly though, I think Kelly was concerned about Vicks' high turnover rate. A failed play is one thing, but an interception is much worse. Obviously the fumble makes this reason less convincing in hindsight, but Chip didn't call it in hindsight.

There's another reason to love this play, and it's one that Chip is very aware of: this gambit is pure video bait, something intriguing and very different for Detroit's coaches to waste time studying and practicing against. Let's face it, it's more fun for them look at and plan against something crazy like this: a 6'6" quarterback on the right sideline! The fact that we don't know what the actual play was going to be -- since it was aborted by the fumble -- paradoxically makes it an even better distraction.