On the morning of Sunday, March 16, 2014, John Moffitt woke on the floor of a Chicago holding cell, his mouth bloody, his memory blank.

The catalysts for his reckless night had still been swimming through his bloodstream when police had locked him in the cell with 40 other men, having arrested him on charges of battery and drug possession after Moffitt, standing 6-foot-4 and weighing more than 300 pounds, had tussled with a bouncer at a nightclub called Underground. The police report had catalogued the scope of Moffitt's thrill-seeking: He had on his person 10 grams of marijuana, four ecstasy pills, and a gram of cocaine, all stored in a sunglasses case.

Once inside the jail, Moffitt had pulled the black, collared sweater he was wearing over his head and passed out. When he came to, he didn't immediately remember what he had done or why he was there, and he didn't know that his mugshot - showing him puffy-eyed, with a busted lower lip and a vacant look on his black-bearded face - already had been made public. So at his arraignment, when the judge asked him a question, it struck him like a thunderbolt.

Aren't you that football player?

No, he was not a football player, not then. He had been one before, spending three seasons in the NFL with the Seattle Seahawks and the Denver Broncos before he walked away from the sport in November 2013. And he became one again in late June, when the Eagles signed him to a one-year contract to have him compete for their starting right-guard position this season. But for the 19 months between his sudden retirement and his return, Moffitt - and only now that he had left the game and come back to it could he see this - had been without an identity.

He had been held up as a symbol of football's uncertain future, a free-thinker at the center of a cause celebre: a man in the prime of his life and career, an alumnus of the University of Wisconsin with a degree in sociology, deciding that he could no longer abide the physical and mental debilitation that the sport inflicted on its competitors, sacrificing $1 million in pay for his choice. He spoke at length, with the Associated Press and the New York Times, in particular, about his reasons for retiring. He read Chomsky. He listened to Hendrix and the Doors. He had been suspended for the first four games of his rookie season, 2011, because he had taken Adderall - a medication to combat attention-deficit disorder, a medication that a doctor had prescribed him. Did that make sense? Was that reasonable?

He didn't like being expendable. He didn't want to be a cog in the football machine anymore. He wanted freedom, the opportunity for exploration. Instead, he partied past the point of mere pleasure, unleashing an addiction that had been dormant within him.

"When you have a problem, you don't realize you have a problem until you realize you have a problem," Moffitt, 28, said after the Eagles practiced one day earlier this month. "I'm like, 'Oh, my God. I've worked for so long. I want to blow off steam.' And then it's like, 'When are you going to stop blowing off steam, John? It's been five months.' "

After his arrest in Chicago, Moffitt pleaded guilty to battery and paid a fine. The drug charges were dismissed. But the incident, and the fear that he might spend more than a night in prison, inspired him to enter Passages, a rehabilitation center in Malibu, Calif., that offers a holistic approach to treating substance abuse. ("We have 20-plus modalities of treatment," including art and meditation therapy, a representative from the center said in a phone interview.)

When he completed the program, he was sober, really, for the first time since he was 16, and after a year of being clean, he found nothing in his life that gave him the same daily fulfillment that football had. He had rejected the machine, but in a way, he needed the machine, and perhaps now he was better able to survive within it.

"Nothing is perfect in any job," Moffitt said, "but maybe the magnitude of it wouldn't have seemed so large if I wasn't always messing with my state of mind."

He decided in February to return to the NFL, waiting a month before making the announcement, battling his own ego as he anticipated a skeptical, even disdainful, reaction from the public and people around the league. Ultimately, he hoped everyone would understand that he had changed, that he couldn't live with the regret of not giving football another try.

"If you're honest," he said, "I do feel like they'll give you the benefit of the doubt."

The Eagles did. They had no clear-cut starter at right guard. Moffitt was worth at least a look. Before he signed with them, he met with Chip Kelly.

"I talked about my background very honestly," Moffitt said, "and he shared similar stuff - not with his background, but people he was close with."

The coaches keep an eye on him, he said, asking often if he's OK, if he needs anything, and Moffitt reminds them that he's seeing a therapist, that there is only so much they can do for him.

He doesn't know if he'll even make the Eagles' final roster. It would be a hell of a thing if he did, because then John Moffitt wouldn't be that football player anymore. He would just be a football player again. The difference would mean only the world.

@MikeSielski