After the first official practice of the New England Patriots training camp, wide receiver Austin Carr was one of a few players (with quarterback Jacoby Brissett) that stayed on the field for additional reps after most of the team had left.

“Yeah we’re just building some rapport,” Carr said. “Building some rhythms together. “There’s a lot more hours with the playbook. A lot more hours with coaches and meetings. I don’t have to write papers anymore. I’m not worried about classes right now. As fun as being a student was, now I get to focus fully on football.”

For Carr, it’s almost like he’s starting all over again. To prove his worth as a valuable piece of a football team. The defending Super Bowl champions to be exact. At Northwestern, Carr joined the team as a walk-on. He eventually scrapped his way to a starting position and a scholarship before winning Big Ten Receiver of the Year during his senior season.

Now, Carr is an undrafted rookie free agent on the Patriots. During the middle of practice, Carr trotted across the field with Tom Brady, Julian Edelman and the rest of the quarterbacks and wide receivers to begin a drill. The crowd cheered.

“They told us about the environment,” Carr said. “They told us about the atmosphere. They told us to be ready about 10,000 people out there screaming. They’re not screaming my name. I just have to put my head down and work.”

Carr’s first day included a nice grab in the corner of the endzone over defensive back Will Likely on a pass from Jimmy Garoppolo in drills. The crowd cheered as Carr hauled in the pass, and the defensive backs were forced to do pushups as punishment.

Carr made a few nifty catches on the day, but when asked about his performance, all he could do was praise the organization that’s given him a chance.

“Playing against the best will hopefully eventually make you the best,” Carr said. “Guys here are quick and fast and smart. It is different than college where dominating comes a bit more naturally. Here, not so much. The most surprising part is how complex the offense actually is, and how quickly you have to respond. At Northwestern, we had a similar kind of design to our offense, this is just times 10.”

Carr said he went back to Evanston, Illinois for some workouts and said he still keeps in touch with Northwestern head coach Pat Fitzgerald, calling him “a coach for life.”

Carr is attempting to make a team that is stacked with wide receivers. Among returning players such as Julian Edelman, Chris Hogan, Danny Amendola, and Malcom Mitchell is Brandin Cooks, who the Patriots acquired for a first-round and third-round draft pick. A blockbuster trade. That leaves likely five locks at a position the Patriots sometimes keep just five players, meaning Carr will have to shine.

“In one sense you’re in the moment,” Carr said. “But I’m looking for the marathon, not the sprint. And that means putting one day after another. You guys probably get bored hearing that all the time, but it’s one day after another. That’s how I earned my way at Northwestern, and I know that’s how I’m going to earn my way here.”