Damar Hamlin was easy to spot on the sideline of the Buffalo Bills’ practice field Tuesday morning.

Most of the defensive players on the “blue” side wore helmets for the team’s optional workouts. Hamlin’s head was instead covered in a pink tie-dyed beanie with a Bills logo, a sign that the safety was not yet tackling teammates in summertime workouts.

It was the second on-field workout for Hamlin, 25, since he received lifesaving care after undergoing cardiac arrest on the field during an N.F.L. game on Jan. 2. Three specialists unanimously cleared Hamlin to return to football in April and he participated with teammates in drills last week during the team’s first off-season workouts.

As the voluntary training resumed on Tuesday, Hamlin’s pink head gear was one of the only signs that the mundane drilling and stretching marked a milestone that was nearly unthinkable just a few months earlier.

Hamlin walked with his teammates up and down the field, located next to the Bills’ Highmark Stadium, as players scrimmaged. The third-year defender participated in a few drills and at one point ran a route with the offense, catching a leaping pass in the end zone from backup quarterback Matt Barkley.

At one point during the sunny midday workout, which lasted nearly two hours, Hamlin got ribbed during a chat with fellow defensive backs Jordan Poyer and Micah Hyde.

“I was teasing him a little. I told him he was looking swole,” Hyde said after practice. “He told me he got to lift a little weight yesterday.”

The near normalcy of Hamlin’s appearance in a football workout is a far cry from the tense nine minutes last January during which trainers and physicians performed CPR on him while television cameras captured the grief-stricken faces of Bills players, some of whom wept and prayed. Hamlin was revived and was taken off the field in an ambulance.

After his release from the hospital later that month, Hamlin made a number of high-profile public appearances. He helped to honor Bills training and medical staff as well as the hospital employees who treated him during a pregame ceremony at the Super Bowl in February. Days before the championship game, Hamlin gave an emotional speech after accepting the Community Award during the N.F.L. Honors ceremony.

In March, Hamlin met with President Biden in the Oval Office and spoke before Congress in support of a bill that, if passed, would fund access to automated external defibrillators in schools.

Last week, the Bills posted a video of several players and staff members receiving training in CPR and the use of defibrillators ahead of Hamlin’s return to the field.

The team’s contact drills are scheduled to begin next week, when Bills players are slated for three practices. Though General Manager Brandon Beane said Hamlin had been “fully cleared” for football activities, Hyde acknowledged that players can experience an initial reluctance to return to the violent collisions that are inherent to the game.

Hyde injured his neck last season during Week 2, and underwent spinal surgery to remove a herniated disc and fuse two vertebrae together. He returned to practice on Jan. 12, just days after Hamlin’s near-death experience.

Hyde said anytime a player comes back from an injury, “There’s a little mental block to get out there and go play fast. It’s such a violent game.”

He dealt with it by mentally preparing for his comeback, telling himself, “I’m ready to go, I’m ready, I’m ready to hit, I’m ready to tackle, I’m ready to do whatever.”