The play that ruined Dexter McDougle’s senior season at Maryland did not ruin his life. It dislocated his right shoulder and fractured his scapula and ended his collegiate career and, for a few hours, sent his world tumbling down, as he put it. But he did not pout, and he did not sulk, and he did not withdraw from his teammates, who needed him as much he needed them.

The Jets decided to select McDougle, a cornerback, in the third round of the N.F.L. draft for several reasons — his speed, his ball skills, his versatility — but also, in part, because of the events set in motion by that play, a diving tackle last Sept. 14 at Connecticut.

They praised his instincts, how at the snap of the ball, McDougle knew to abandon his receiver and zip toward the right flat, where he upended the tight end for a minimal gain. Terry Bradway, the senior director of college scouting, said that McDougle rated the smartest among the cornerbacks who visited the team before the draft.

The Jets also admired McDougle’s reaction to the aftermath, how he spent the next three and a half months, his arm in a sling, acting as a player-coach. He attended every practice, where he would demonstrate proper technique to his replacements. He attended every film session, where he would offer tips to his fellow defensive backs. He attended every game, where he would sit in the coaches’ booth, wearing a headset and with binoculars at the ready, to chart plays and relay observations to the sideline.

“He was still playing every play in the games,” Maryland Coach Randy Edsall said in a telephone interview. “He just wasn’t out there physically doing it.”

To McDougle, doing anything else felt unnatural, and wrong. Since his freshman year at Stafford High School in Falmouth, Va., he had been policing teammates, demanding excellence and accountability, and acting otherwise would have been insincere. If they complained about doing wind sprints, he would admonish them — and then finish first every time, backing up his words. In the weight room, he would chide anyone sitting down. Those who blew a coverage, or showed up tardy, or dared not work as hard, and for as long, risked a rebuke from McDougle.

“We’re here to work,” McDougle said Friday, when the Jets opened their rookie minicamp. “I’ve never had any other mind-set.”

One day at Maryland, after some teammates failed to make it through a conditioning session, he addressed them. “You want to win the A.C.C.?” he said to them. “How do you expect to be champions if you can’t finish a workout?”

He expected so much, of his teammates and of himself, because he knew what it felt like not to play, and he hated it. A hand injury cut short McDougle’s junior season at Stafford, limiting the game film that prospective colleges could view. He played cornerback and safety, running back and receiver, even quarterback in the Wildcat formation, and then, all of a sudden, he could play none.