An NFL career ends in different ways. Players become too old, too broken down, too expensive or just not good enough anymore.

They're often shoved into retirement as teams find the next man for the job.

John Carlson unexpectedly left the game of his own volition.

He walked away from a secure roster spot in Arizona, a $1 million salary and a situation he loved.

He felt healthy and had no concussion symptoms at the time. He hadn't even reached his 31st birthday yet. Nobody was pushing him out the door.

So why abruptly retire? Why leave before his meter had expired?

Carlson says he just reached a point after seven NFL seasons where he had enough of football and wanted to devote more of himself to his family.

"It was clear already that I didn't have that same passion and love for the game that I had in the past," said Carlson, the Litchfield native and former Vikings tight end.

Early retirements among NFL players made a splash in headlines this offseason. None drew more attention than San Francisco 49ers linebacker Chris Borland because his case was so unique and alarming.

He was a young, budding star with a bright future. But concerns over his long-term health and potential head trauma led Borland to retire after one season.

Carlson says his situation is a little different. He has a history of concussions, including two when he played for the Vikings and one as a member of the Seattle Seahawks in which he was knocked unconscious in Chicago.

Carlson weighed the game's inherent health risks and his own history, but two other factors drove him to retirement.

His passion for the game began to disappear. And the commitment that's required to survive in the NFL was interfering with his home life.

The Carlsons have three kids under age 5. The two oldest understand when he's not at home now. Or when he's home but distracted by something else.

Carlson decided to address his priorities.

"It was obvious that I wasn't nearly the husband and father that I want to be," he said.

His decision came in early May after spending the day participating in OTAs at the Cardinals facility. Carlson went home, sat down with his wife Danielle and made a list. Two lists, actually.

On one side, they wrote down reasons why Carlson should continue to play football.

"It was a long list," Carlson said.

The other one contained reasons why he should retire. Carlson had begun to feel differently about football, emotions he hadn't experienced previously.

The couple discussed the situation for several hours. Carlson returned to work the next morning and told the team he was retiring, an announcement that caught teammates by surprise.

The Cardinals issued a statement that didn't give a reason. Carlson shed light on his thought process last week on the final day of his six-week visit to Litchfield.

"I think once that switch turns off in your head," he said, "I don't believe the game is safe to play anymore."

Carlson wasn't a Pro Bowl tight end. He had to work hard to avoid being chewed up and spit out.

"I didn't go home after practice and just sit around and watch TV," he said.

He stayed late after practice getting preventive treatment. He made regular visits to a chiropractor. He hired a personal trainer. He used a hyperbaric chamber for recovery. He wore compression sleeves on his legs at night.

He says he wouldn't have lasted seven years in the NFL without all those devices. But he grew tired of the sacrifices required of his family.

"I know there are many people in many professions that that's their reality [too]," he said. "But in football, our careers are condensed. I feel very fortunate to be able to play seven years and to have the flexibility to be able to say, it's time to move on. Time to find something else that I'm passionate about that maybe works a little bit better for our family life."

He isn't sure what that is just yet. But he's happy. As NFL training camps begin to open this weekend, Carlson is on a family vacation in Florida.

He says he doesn't feel weird not getting ready for a season.

"When September rolls around, that might be a little more difficult," he said. "But it's part of the deal. I know there will be things that I miss the rest of my life. But I can't go back."

Chip Scoggins chip.scoggins@startribune.com.