Measuring their speed, strength and verticle jump, that's the easy part.
The far more difficult aspect for NFL teams preparing for the draft or free agency is finding guys who can fit into what they want to do on the field, but who can also fit into a team's culture.
And for an Eagles team coming off a Super Bowl championship, it's one of the big challenges of the offseason.
The Eagles have built a powerful chemistry and culture over the past two years that was pivotal in their drive to the franchise's first championship in 57 years.
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It was a remarkably close team, a remarkably unselfish team. And now the Eagles are in the process of trying to add talent without ruining that unique chemistry.
Eagles executive vice president of football operations Howie Roseman said Thursday the Eagles' scouting department spends a tremendous amount of time and resources not just evaluating players' physical attributes but trying to determine whether they're good fits for what the Eagles have built.
"I think that's one of the conversations that we probably have the most," Roseman said. "Background's really important. We've had some guys who've come here, who've maybe had a (bad) reputation and fit really well, and there's also the flip side of that.
"So you try to balance all of those and really rely on coach (Doug) Pederson and his leadership council and the ownership he gives them."
Roseman revealed that he, vice president of player personnel Joe Douglas and Pederson actually involve players already on the roster in the decision-making process.
"We talk to our players about a lot of things, and we talk to them about guys that we're going to potentially bring in," Roseman said. "We try to pick their brain."
It's not a perfect process. Every team has been burned by a Darryl Worley. But the Eagles clearly are doing a better job than most teams getting 53 unique individuals to mesh together.
"I accept responsibility for the mistakes we made, that's on me," Roseman said.
"But we try to get a lot of information and then also talk to our players so a lot of these moves that we've made the last two years … and that's probably not the norm in the National Football League, but that's really from the leadership of coach Pederson and what he wants us to do."
Roseman mentioned something called the "Co-habitation Matrix," devised by Douglas and Eagles director of football administration Jake Rosenberg - "and Keanu Reeves," Roseman joked. That's basically a way to connect anybody in any role within the organization that has had any previous experience at a previous spot with potential new additions.
It's all a part of minimizing the risk of shattering the franchise's powerful culture.
"That's something that we work so hard to build and it could be the hardest thing to build and it could be the easiest thing to lose and that's something that we have been working hard on, is just pinpointing the guys that can come in and just add to our culture," Douglas said Thursday.
"Chemistry really isn't a thing you can quantify. It's not an objective thing, but you know when you've got it and obviously for us to do what we did last year we had it. So now it's us trying to keep adding to it."