PHILADELPHIA — Charles Johnson had lost his smile.

He wasn’t in love with the game of football following his up-and-down first stint in the NFL. He spent last season out of the league after being cut by the Jets following the preseason.

A few months later, he was happy again. It helped that the Philadelphia Eagles called and offered him a job.

In between the release from the Jets and signing with the Eagles, Johnson starred in the now-defunct Alliance of American Football league. During that time, he got his smile back.

“I played freely, [there were] no politics involved,” Johnson said Wednesday, reflecting on his AAF experience. “The best players were going to play … it was all about the love of the game.”

Johnson produced 45 catches for 687 yards and five touchdowns for the Orlando Apollos, a team coached by collegiate legend Steve Spurrier. The “Head Ball Coach” challenged his players with a blank slate each week — as in, everyone had to keep earning their jobs on a weekly basis.

That included Johnson, one of the most experienced former NFL players in the league with time spent in the Cleveland Browns and Minnesota Vikings organizations.

If Johnson wanted to play, he needed to earn it, every week. Then, every week, he stood out as Orlando’s best wide receiver.

His positive energy returned.

“On film," Johnson said, “I see myself smiling.”

Johnson’s friends noticed his grin on television. It was a sign that he could bounce back from the rut he had been in during his first NFL stint.

The AAF folded in April. Johnson, one of the league’s few standouts, was surprised by the AAF’s implosion. He’ll never forget the experience.

“The AAF was really fun,” Johnson said. “I really miss it. I miss the guys that I played around and I miss all of the atmosphere. It was great, I thought it was going to be a really good league. Unfortunately, it folded but that’s how it is.”

Johnson quickly garnered interest from the NFL due to his strong performance in the AAF. The veteran wide receiver signed with the Eagles just a few weeks after the team traded for returning deep threat DeSean Jackson.

Now, Johnson has a legitimate opportunity to earn a role on the Eagles’ roster, despite the return of Jackson and the selection of second-round pick J.J. Arcega-Whiteside. The 6-foot-2, 216-pound receiver lined up with the first-team offense throughout organized team activities as starter Alshon Jeffery skipped out on voluntary workouts.

Johnson knows each rep that he takes is important.

“I can’t take anything for granted,” Johnson said. “We’re not promised to be here tomorrow.”

The stakes are high for Johnson, who hasn’t caught a regular-season pass since the 2016 season. He is competing for a roster spot in Philadelphia, all while his ill father and young children remain in Kentucky.

He misses his family but he knows this, the NFL, is where he wants to be. It’s worth the sacrifice.

“I think about it all the time, what I’m giving up to be here,” Johnson said. “I’m not going to go out there and waste it.”

Johnson has taken advantage of his extra reps in workouts. The veteran receiver has been catching passes from starting quarterback Carson Wentz and the two have already developed some chemistry.

“It’s coming along,” Johnson said. “I’m starting to get more throws with him in individual [drills]. Just trying to see how he throws the ball, how it comes off his hand and he can see how I run routes. It’s something that’s going to take time.”

Johnson was the most experienced wide receiver on the field during Wednesday’s OTA workout. Jeffery, Jackson and Nelson Agholor took the day off and Johnson was asked to take on even more reps.

The 30-year-old is competing for a job amongst 20-year-olds who have barely played professional football, but he’s not worried about being too old.

“In the NFL, age is always going to be something everybody looks at,” Johnson said. “I just don’t need to focus on that. I still feel young. I still feel like I can go out there and compete with anybody.”

The extra reps in practice have tested Johnson’s conditioning. Unlike his teammates, Johnson was playing football throughout the spring in the AAF.

“It’s always good to go out there and get the extra reps,” Johnson said. “Sometimes, it’s like ‘hey, my legs, I’m running a lot,’ but you’ve just got to bite down and grind. You’ve got to go out and take advantage of those opportunities.”

With a renewed passion for the game, Johnson has the desire to improve day in and day out.

“I kind of lost that love at one point in my career in the NFL,” Johnson said. “And I found it again, so I’m just trying to enjoy it, I’m trying to be happy with everything and not worry about too much.”

When minicamp ends next week, Johnson will take a short vacation before beginning his preparation for training camp, where he’ll compete for a roster spot with youngsters like Mack Hollins, Shelton Gibson and rookie DeAndre Thompkins.

If Hollins, Gibson and Thompkins look over at Johnson in late-July and can see his pearly whites, they should be worried. That means he’s winning.

“Usually when I’m smiling, I’m at my best,” Johnson said. “I found that love again and I’m just trying to keep it.”

Mike Kaye may be reached at mkaye@njadvancemedia.com. Follow him on Twitter at @Mike_E_Kaye. Find NJ.com on Facebook.