On a Thursday afternoon well into the season, Lions coach Dan Campbell leaves his team with some encouraging words, the circle breaks and the players make their way from the practice field to the locker room.

One player, however, isn’t going anywhere.

Amon-Ra St. Brown starts running sprints as if they are routes in a no-huddle offense. He goes about 10 yards forward, 5 yards to the left or right and 10 yards ahead before jogging back to the starting point and beginning again.

By the time he finishes the sprints, sweaty and breathing hard, he is one of the last remaining on the field. Then he walks to the sideline and turns on the Jugs machine, which makes a faint whirring sound. As the balls hit his hands, a clap and an echo.

St. Brown won’t leave the field until he catches 202 balls. He has done this almost every day since he was in high school. The number is 202 because he saw another player with good hands catching 200 balls, and he wanted to be better.

This commitment is why St. Brown, through 25 games, has caught more passes than any player in league history who was not selected in the first three rounds of the draft.

“He works like it’s the last day he’ll ever be able to play the game,” Campbell says. “Every rep he takes, he works the detail of the route. He catches and he finishes every play. There’s never a catch and then he just kind of glides through it. He’s trained himself that practice is very much game-like to him. His approach to the game is as good as I’ve been around.”

It’s almost too good. At times, Campbell acknowledges, he has to limit St. Brown’s practice reps — “save him from himself,” he says — because St. Brown wants to take every last one, and what’s most important is that he’s fresh for the game.

St. Brown understands his coach’s concerns. That’s why he sleeps eight or more hours nightly and nine or more the night before a game.

But when he pads up, he gives no thought to self-preservation.