Nugent-Hopkins' participation was in doubt due to left shoulder discomfort he felt playing for Oklahoma City in the American Hockey League. Camp begins Monday.
"I think definitely the biggest factor was just making sure that my shoulder was good to go, and once we got that all settled I think it was a fairly easy decision for me," Nugent-Hopkins said on the Oilers' website.
He never has represented Canada at the WJC. As a 17-year-old in 2010, he was among the last nine players cut on the final day of camp. Last year, the No. 1 pick in the 2011 NHL Draft was with the Oilers, scoring 52 points in 62 games and becoming a Calder Trophy finalist.
"It's a good chance to play for my country," the 19-year-old said. "Growing up I've always watched the World Junior Championship, and I never got a chance to play last year or the year before, so it is going to be awesome for me to get that opportunity. We all want to bring back the gold, so that's definitely the biggest reason."
Nugent-Hopkins, who missed 20 games with the Oilers last season with shoulder injuries, was hurt in a game last weekend and returned to Edmonton for a full evaluation.
"It's always been my left shoulder, but, I mean, it's not anything bad at all this year," Nugent-Hopkins said. "It's been feeling really good. We just wanted to make sure that it was ready to go, and I think I had a really good week of rehab and strengthening, so I'm excited to get going."
Nugent-Hopkins is among 21 forwards on Canada's 36-player roster for camp, to be held at the Markin MacPhail Centre at Canada Olympic Park in Calgary, Dec. 11-13.
Nugent-Hopkins, who has eight goals and 20 points in 19 games with the Barons this season, was the only AHL player invited to camp.
"I've talked to quite a few guys who have played in the [WJC]," he said. "They all said it was a great experience, so it definitely helped in making my decision."
Friday, Hockey Canada announced that forward Colton Sissons of the Kelowna Rockets in the Western Hockey League would be unable to attend camp due to an upper-body injury.
The WJC will be held in Ufa, Russia from Dec. 26-Jan. 5.