Some get this right away. Some take longer. Some never do, which LeSean McCoy at least suggested yesterday is why DeSean Jackson is no longer an Eagle.
Ifeanyi Momah, an intriguing story last year at this time, needed the humbling experience of getting cut by the Eagles last summer, of watching others re-signed to the practice squad, of sitting in his Long Island home and waiting on a phone call from some other NFL team that never came, before Kelly's little catchphrase really sunk in.
"I sat back at home a lot last year just thinking about all the things I could have done," Momah, 24, was saying after practice yesterday. "All the things they told me to do that I didn't . . . Like I was at home and I heard a couple of guys that were let go were re-signed and I was thinking, 'Why didn't I get re-signed?' And I thought about certain things I didn't take advantage of. Some days I came out here just to get through it last year. You just can't do that."
So Momah is back, all 6 feet, 7 inches of him, trying to re-establish that intriguing story line. In a league that is even more in love with bigger, physical cornerbacks than it was a year ago, the idea of a 6-7 wideout with 4.4 speed in the 40-yard dash is clearly worth a second look, or so Kelly and his brain trust thought.
Plus, Momah wasn't himself a year ago when he arrived as an undrafted rookie free agent. That 4.4 speed slowed to a crawl as he tried to absorb Kelly's intricate offense while simultaneously regaining the football shape lost during his recovery from a severe ACL tear suffered in 2011 as a senior at Boston College.
"He missed an entire year," Kelly said. "So there's obviously a bit of rust he had to knock off a little bit."
Said Momah: "The one thing I remember is being so tired. Getting acclimated to this pace. Not just the NFL, but this offense. I was kind of like dead-legged and didn't know what the hell was going on. But now I feel a lot more free because I'm more confident. And because I'm playing freer, I have more energy and I just feel a lot more comfortable as a receiver right now. I feel like it's a big difference from last year."
Kelly agreed. "We have seen a marked improvement from last year to this year," he said.
"He's not just trying to figure out, 'Where do I line up at the snap?' He already knows where he's going and he's lining up and reading coverages and has a better understanding in terms of how it's supposed to look. I think he feels more comfortable here. There's not a newness in terms of this is not my first time doing this, and what does this look like,where am I supposed to be, how does that work?' "
What that means amid the crowded and experienced group of receivers he is competing against is unclear at best. Kelly likes to say, as he again did yesterday, that any of the 90 players in this camp are capable of making his team, and that "When we talk about investing in yourself, we are challenging them to understand that with every action, you have consequences. They can be positive or they can be negative. If at the end of the day your goal is to make this football team, or your goal is to be a starter, or your goal is to be an All-Pro, you have a say in that matter. That's what we are trying to get across to our guys."
Momah insists he gets that now. No wasted practices, no wasted plays, no holding back. Invest in yourself.
"I'm realizing my hands are huge," he said. "My body's big. It's like basketball. Go snatch the ball out of the air, stay on your feet, go score some touchdowns. That's what I love to do and it's what I've been doing my whole life."
He'd love to stick with the Eagles, he said, "But at the same time, I'm going to make sure I have some film just in case, because we have some really good receivers here. Established receivers. So whatever happens, I'm going to make sure that I'm somewhere. I'm going to be on someone's roster.
"Last year, I just wasn't confident. I just felt out of place. I wasn't good out of my breaks. I felt like I was slower than I should have been. I think it was all in my head. This year I feel a lot more comfortable as a wide receiver. And I know I'm going to go out there and kick ass."
On Twitter: @samdonnellon