Kelly's offense fits another guy pretty well, also. Thursday night, LeSean McCoy gave us a sneak peak of what he potentially can do in it, rushing for 47 yards and a touchdown on eight carries in his first work of the preseason.
He had three carries of 7 yards or more, including a 21-yard Barry Sandersesque run late in the first quarter that set up the Eagles' first touchdown.
On a first-down play at the Carolina 28, Shady took the handoff from quarterback Nick Foles, bounced outside when nothing was open inside, faked cornerback Drayton Florence and linebacker Thomas Davis right out of their jocks, and cut across the field like a guy going east in a westbound lane.
Finally was brought down by cornerback Josh Thomas at the 7.
"The line had it blocked pretty well," McCoy said. "They did a great job all night making holes. I just hit the crack, saw some open field. I gave some moves and felt one of the defenders coming in pursuit, and I went. I should have scored."
He scored later on a 1-yard run around left end, going in untouched. Like most of the rest of the starters, McCoy sat out the second half.
"I could have gotten a little more work," he said. I mean, as a whole, I think our offense should have put more points on the board. I think in the first half, we made small mental mistakes and had turnovers [a Foles interception in the red zone, a fumble at the Carolina 19 by backup running back Chris Polk], which killed us over the last 2 years. So I think we have had enough of that, and it's time to change it. I think as an offense, we needed more work."
They'll get it next Saturday against Jacksonville, when McCoy and the rest of the ones likely will play at least three quarters, maybe more.
Under Andy Reid, McCoy didn't get much work the previous two preseasons. Big Red preferred to keep his star running back out of harm's way. He had only nine carries for 24 yards last summer. Had 11 carries for 36 yards two summers ago.
Didn't seem to be a problem for him. Two years ago, he rushed for 1,309 yards and an NFL-high 17 touchdowns and was a first-team All-Pro selection.
But he's in a new offense now and needs all the work he can get. Particularly since he missed almost a week of practice and the first preseason game with a minor knee injury.
"LeSean needs to practice and LeSean needs to play," Kelly said. "He'll be the first to tell you that. So, you know, you're rusty at times.
"Obviously, he's extremely talented. But even he said it when he came back. He missed a couple of days of practice, and when he's out there, he's kind of off a little bit, because you need to get into rhythm. I think he wanted to play longer. But we have to be smart with him."
Kelly's offense looks very, very good on McCoy. With the Eagles' athletic line blocking for him on inside and outside zone runs, a 1,500-yard rushing season is not out of the realm of possibility for him if he can stay healthy and his blockers can stay healthy.
Last year was disappointing for him, both from an individual and team standpoint. Injuries KO'd three of his linemen - left tackle Jason Peters, center Jason Kelce and right tackle (now right guard) Todd Herremans.
McCoy missed four games with a concussion. His yards-per-carry average dropped from 4.8 in 2011 to 4.2. He managed only two rushing TDs. Everybody talked about Adrian Peterson, Alfred Morris, Marshawn Lynch and Jamaal Charles. Nobody talked about McCoy.
He wants to change that this season.
"Everything that coach Kelly has taught us and told us about this offense has been correct, as far as the fast tempo and keeping the defense off-balance," the 25-year-old running back said.
"It's so hard for defenses to get their calls in, because we are going so fast. It's effective. I also think that when you execute and know what you are doing, it's also effective.
"The thing about our offense is that so many players want to make plays, and this offense gives you great opportunities to make the plays. We have so many different weapons. So it's only a matter of time until we see how this thing works out. I'm excited."
So are his teammates.
"It's fun having him back out there," Kelce said.
"That [21-yard] run, that's a run where he can break a guy's ankles," linebacker DeMeco Ryans said. "Shady's got the moves. Shady's a great back and makes a lot of people miss in the open field. I'm glad I'm not out there needing to tackle him."