By the time a large crowd had gathered in a corner of the Eagles locker room early Friday morning, all of them closing in on Josh McCown, spearing him with microphones and asking him about his terrific performance in his first game with his new team, Cody Kessler had left Lincoln Financial Field. He had been gone a while, having pulled a T-shirt over his head and broken-in jeans over his legs, accepting of the unforgiving reality of his profession.

Kessler had not played particularly well Thursday night in the Eagles’ third preseason game, a 26-15 loss to the Ravens. Not wanting to risk injuring Carson Wentz, coach Doug Pederson instead started Kessler, who completed 3 of his 5 passes for 35 yards but took a sack on a fourth-and-3 on the Eagles’ first possession, an inexcusable error. McCown then threw for 192 yards and two touchdowns, assured himself of being Wentz’s primary backup this season, and put Kessler’s roster spot in greater jeopardy than it already was.

This was a predictable chain of events after the Eagles’ previous game, in Jacksonville last week, and it was predictable for a single, simple reason: Kessler had suffered a concussion in that game. The Eagles already had lost a quarterback, Nate Sudfeld, for six to eight weeks because of a broken wrist. Maybe they could get by with just Kessler and rookie Clayton Thorson behind Wentz until Sudfeld’s wrist had healed. Maybe Kessler would retain his roster spot, even if he struggled against the Jaguars. Maybe the Eagles would not have to acquire another quarterback.

Eagles quarterback Cody Kessler getting taken down by Jaguars defensive end Datone Jones during a preseason game last week.
YONG KIM / Staff Photographer
Eagles quarterback Cody Kessler getting taken down by Jaguars defensive end Datone Jones during a preseason game last week.

But then Kessler took a wallop, and what happened next was the most predictable moment of the entire predictable sequence. Just as he was starting to run the next play, the officials stopped him. A spotter, an independent athletic trainer, had watched a replay, noticed that Kessler made a telltale irregular movement in the area above his shoulders — “Something tensed up,” Kessler said — and determined that he should be evaluated for a concussion.

Kessler didn’t think he had one. He didn’t want to leave the field. He knew what it might mean. Every NFL player, in the same situation, knows what it might mean. Kessler already had suffered two concussions, in 2016 as a rookie with the Cleveland Browns, and still he didn’t want to leave the field because he knew what it might mean. It might mean that you’ll lose your job.

“That was the biggest thing for me,” he said. “I was trying to tell them, ‘Hey, man, I can pass these tests. I don’t have it.’ But yeah, I guess there’s that transition to the question: How much do you say? How much do you not say? I was frustrated. I wanted to stay in there. But at the end of the day, with your head, you don’t want to play around. As frustrated as I was the other night, wanting to stay in, you have to understand why they’re as cautious as they are.”

So he came off the field, reluctantly. A concussion was diagnosed, and he entered the league-sanctioned protocol. Two days later, the Eagles signed McCown. People wonder why head injuries are such a thorny, challenging issue in the NFL, why athletes are willing to risk their long-term health by playing through concussions, why even an accomplished and respected star such as Eagles safety Malcolm Jenkins might try to hide that he’s feeling dizzy and foggy and disoriented after delivering or receiving a car-crash-caliber hit.

This is it. This is why. Cody Kessler had a job, and he wanted to keep it, and he’s not alone in this league in thinking that way and acting accordingly.

Eagles quarterback Cody Kessler (2) is realistic about life in the NFL. "You've got to have availability," he said.
TIM TAI / Staff Photographer
Eagles quarterback Cody Kessler (2) is realistic about life in the NFL. "You've got to have availability," he said.

“You’ve got to have availability,” he said. “You’ve got to be ready to go. Josh is a great vet. He’s a guy I’ve known for years. I was excited to see him. But yeah, that’s part of it. You’ve got to stay healthy.”

He now has had three official concussions since entering the NFL three years ago, but something else was on his mind after Thursday’s game. He had returned to practice Monday, a quick turnaround, and he said he was symptom-free. Even the specialists, in their examination notes, said so — a point he accented, because he was clear-eyed about where he stood with the Eagles.

“Obviously,” he said, “if I don’t stay here, teams can see that it’s not a red flag.”

One concussion might cost him his job, but three concussions weren’t a red flag. That is the reality of professional football, and it sure seems twisted. You take a shot to the head. No one immediately knows how long you’ll be out of the lineup, and before anyone does, the team signs someone else to take your place. It is nothing if not cold-blooded.

“No,” Cody Kessler said before he left the locker room, “it’s the NFL.”