RIO DE JANEIRO — The Patriots’ Nate Ebner is forgoing football this summer to chase his Olympic dream. Fittingly, it entails practically nonstop running.

That’s the nature of rugby sevens, the fast-paced, lung-searing, seven-person-per side version of the game that is making its Olympic debut at the Rio Summer Games. (Rugby union with 15 players per side was featured in the Games in 1900, 1908, 1920, and 1924.)

Ebner, who grew up playing rugby and converted to football during his junior year at Ohio State, is here in Brazil with the USA Rugby sevens team after being named to the 12-man squad last month.

He is already in better shape than any of his Patriots teammates who are sweating through training camp back in Foxborough. He’d better be for his grueling sport.

“For me, to transition from football to rugby, it was kind of natural because I did grow up playing rugby my whole life, so I did know how to do that whole thing a little bit,’’ said Ebner. “It took some time getting used to it [again], especially the cardiovascular aspect of rugby.

“Football is a very explosive game. It only lasts five or six seconds, and we train that way. I trained that way for eight years straight until I came back to rugby.

“Definitely, there was an adjustment period. [Teammate] Danny [Barrett] has been on me about looking skinny now from when I first came in. There were some things I had to adjust to. The cardiovascular thing, I just knew that was going to be part of it. The rest of it is just kind of go with the flow.’’

Ebner might be geographically far from New England, but the special teams ace/safety isn’t far from his teammates’ thoughts. Special teams captain Matthew Slater showed that during the first practice of training camp when he donned Ebner’s No. 43.

“Yeah, I was aware of that,’’ said Ebner. “That was pretty awesome. He is a class act.

“It says so much about not only him, but the organization and the type of people they bring to that organization that truly care about one another. Matt is a first-class dude. He got my mom a little emotionally worked up about that.

“I just want to say that not only Matt showed me a lot of support, but a lot of guys throughout that organization. The [defensive backs] and coaches and stuff, they’ve all been amazing through this for me. I can’t say enough about that.’’

Ebner is no stranger to playing rugby on a world stage or to another brand of red-white-and-blue uniform. He was a standout on USA Rugby under-19 and under-20 clubs from 2006-08 and was named MVP of the 2008 Rugby World Cup as a U-20 player.

A 2012 sixth-round pick, Ebner is taking a risk with his football sabbatical. The Patriots have a roster exemption for him while he competes at the Olympics, but he will have to earn a spot upon his return.

But the opportunity to compete for an Olympic medal in a sport that was crucial to the bond he had with his late father was too much to pass up. Ebner chose to wear No. 12 because that was his father’s number as a rugby player.

“I had a lot of different emotions when I found out I made the squad,’’ said Ebner. “Obviously, I was extremely happy. I gave this everything that I had. I think seeing my name on that roster was confirmation that I did give it everything that I had. Seeing that was a great feeling.

“It’s not only those good feelings, though. I also had a lot of heartbreak for the other guys that didn’t make the team . . . We’ve become so close over those five or six weeks. It’s heartbreaking, honestly.

“A lot of good feelings, some bad feelings, but ultimately I’m excited — excited to represent not only those guys, but our country and my family and everyone back home.’’

Ebner said he lost a good amount of weight training for the Olympics, though he wouldn’t give a specific number. But he also said it’s nothing he can’t gain back in the weight room.

The first thing he hopes to lift is an Olympic medal. Ebner and the USA Rugby Eagles open group play next Tuesday against Argentina at Deodoro Stadium.

There are three groups of four teams in the competition. The top two finishers from each group and the top two third-place teams advance to the quarterfinals.

Ebner fielded lots of questions from the international media Wednesday. His presence at the Games as an NFL player is clearly a boon for the sport. But he isn’t a football player right now.

He is thankful that the Patriots have allowed him to step away from the team’s pursuit of a fifth Super Bowl ring to tackle the five rings of the Olympics.

“If it weren’t for their support, I wouldn’t be here doing this,’’ he said. “It’s a once-in-a-lifetime opportunity, and to have them back me doing it means the world to me.’’

Christopher L. Gasper can be reached at cgasper@globe.com.