It was Billy Brown's first day back with the Eagles' practice squad, after 10 days of football unemployment. The Eagles, like other teams, run players on and off their 10-member squad of non-roster players, as positional needs arise, or the coaches decide they'd like to take a longer look at someone else.

Brown was not well-rested, however, from his Sept. 10 to 20 hiatus.

"I've never been on a plane so much in my life," Brown, a 25-year-old tight end from West Virginia's tiny Shepherd University, said last week. "I'm used to it now. I never thought I'd say I'm comfortable on a plane, but I am. Came back from Miami last night. The day before that, I was in Carolina. The day before that, I was at Oakland."

With Brown not under contract to the Eagles, he was available to work out for other teams. Not much is said or written about it, but NFL teams work out unemployed players pretty much every week, often on Monday or Tuesday, when most teams don't practice. The team might have just lost a player to injury or might want to update its emergency list of possible signees.

Either way, it's a hectic, not-at-all glamorous process. After a call from the agent, the player is expected to jump on a plane, probably spend the night in a hotel near the practice facility, and show his stuff bright and early the next morning, with little warm up. There is no payment.

"Sometimes, they leave with their shorts and T-shirt that they're given at the facility," said Philadelphia-area agent Jerrold Colton, who has represented ex-Eagles kicker David Akers and Philly native Jahri Evans, a former Pro Bowl guard, among others. "What they get is an opportunity. If they're in a gym working out somewhere, at home on the couch, nobody's seeing them. … Every club sees who works out."

The league's daily waiver wire contains every team's workout log.

"You stay relevant, stay on the radar screen," Colton said. A team might think, "If Philadelphia brought him in, maybe we should," he said.

An NFL personnel executive who preferred not to be named said he'll occasionally see on a workout log a promising player who had fallen off the radar. That might make the exec think, "Hey, I liked that guy, I didn't know he was still doing this."

As for the workout process, players said they rarely meet a head coach or a general manager, unless there is a subsequent decision to sign them.

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Workouts are "basically the same," Brown said. "They vary a little bit. You meet your position coach, a few other coaches, and they put you through positional drills. You run routes, tight-end blocking, all that kind of stuff."

Brown went 0-for-3 in his workouts and was happy to return to the Eagles.

The teams "told me and my agent that they liked what they saw, but we didn't sign, so, [I] got to keep working, obviously," he said.

It can be a long, hard slog. Florida-based agent Brett Tessler has a client, Vikings offensive lineman Mike Remmers, who was cut seven times in five years before, in his second stint with Minnesota, he established himself enough to sign a five-year, $30 million contract, with $10.5 million guaranteed at signing.

"If it's somebody you believe in … it can get discouraging, and you need to let them know, 'Hey, I've experienced this a lot over the years. … as long as we keep getting interest, there's a chance for great things to happen,' " Tessler said.

Guys on the fringes of the league are scrambling for modest stakes. For players on a team's 53-man roster, the league's minimum salary is $450,000 a year. The practice-squad minimum is $7,600 a week, which works out to $129,200 for the full 17 weeks.  Five weeks on a roster pays more than a whole season on a practice squad.

Each team has a few practice-squad guys who are being paid more than the minimum, a sign that the organization really sees something in the player. Quarterback Nate Sudfeld came to the Eagles' practice squad last year despite a practice-squad offer from the Redskins, who drafted him the year before. Philadelphia was willing to pay Sudfeld his NFL roster salary.

The other teams see this information as well. They can't work out a player on another team's practice squad, but they can sign them to their roster. That was how Sudfeld ended up on the Eagles' 53 last season – he drew interest from Indianapolis after it was apparent Andrew Luck wasn't going to play in 2017.

Colton said tryouts usually are arranged a few days in advance, maybe at the end of the week for a workout early the next week, unless someone goes down in a game at a position where a team is going to need immediate help.  Then, the call to the agent comes during the game, or right after.

Usually, it's from a mid-level personnel exec. The team wants to know whether the player is healthy and available, and his contact information so a plane ticket can be emailed. Agents, who aren't making any money off unemployed clients, make sure they are available.

"I almost never turn down a workout," Colton said. "If the guy is sitting on the street, you gotta take that opportunity, no matter what. The only time you turn it down is if you have multiple teams trying to work your guy out at once. In that case, you have to really try and make a determination as to where his best option would be."

Early in the season, workouts tend to be general – a bunch of guys just got dumped on the market in the cut down from 90 to 53, so Team X wants to bring in a half-dozen linebackers next week, to update its lists. Probably, nobody is getting a job out of it, right away.

"It's useful to get guys in that your pro scouts like, that you don't know as well," the NFL personnel guy said.

Later in the season, teams have seen who is on the market and are more focused – maybe they've had multiple injuries at linebacker, and they bring in a couple of guys, intending to sign one.

A player can work out a whole bunch of times without being signed. Wide receiver DeAndre Carter spent the first two weeks of this season playing for the Eagles. Now, he's on the practice squad. Those were the first two weeks Carter ever spent on a 53-man roster, in four years of fighting for a foothold. This is his fourth practice squad, but in 2016, after New England released him just before the season, nobody picked him up all year.

Carter recited his list of workouts, pausing at times to summon the next memory: "Tampa Bay. I worked out for the Bills, for the Raiders, New England, the Niners, the Colts, Jacksonville."

Players who are not even on a practice squad need outside income. Carter worked as a substitute teacher in California, a flexible job that did not involve commitment. When he needed to fly to Buffalo on a day's notice, he could.

"You still gotta work out to stay in shape," Carter said. "It kind of takes normal jobs off the table. For me, I was sub teaching. I would suggest that for anybody that's in-between teams. Your hours are 8 to 3 or whatever the school day is; you still have the rest of the afternoon."

Carter said he started to see the same receivers at each workout. "You meet a couple guys around the league that way, which is good."

At Billy Brown's Oakland workout, he was happy to reconnect with Joe Callahan, who was working out at QB for the Raiders after spending the preseason with the Eagles. But the workout players don't usually interact with players on the team.

"If you know people on the team, you meet them, say, 'What's up?' For the most part, you don't know anybody," Brown said.

The workouts don't last long. Usually, when the team asks a player to stick around and take a physical, that's a good sign. Otherwise, it's back to the airport. The team will tell the agent the outcome.

"It's a quick process, quick turnaround," Carter said.

Tessler said an agent doesn't only need to encourage his guys to keep going, to push through disappointment. Sometimes, he needs to have the other conversation – teams aren't calling. It might be time to think of what comes next, after football.

"No visits, no workouts, no nothing, no pulse. As an agent, if you have a good, honest relationship with your client, and it's somebody who's intelligent, accountable, and realistic, they themselves will realize before you even have to tell them," Tessler said. "A good agent keeps their player's expectations realistic.

"You don't want to allow somebody – you don't want to see somebody you like and care about wasting their time."