The 25 invited players are to arrive on Thursday for a three-day camp before heading to Sweden for final preparations. The championship begins Dec. 26 in Malmo, Sweden.
Dumba, who was among the final cuts the last two years, is expected to play a big role on defence for a Canadian team looking to end a four-year gold medal drought.
The Minnesota Wild, who kept the six-foot, 183-pound Dumba out of training camp but used him in only 13 games, finally opted to assign him to the Canadian junior team.
"It's been tough on me the last two times," Dumba told the NHL club's website. "Being the last cut last year, it hurt.
"It sucked not being able to represent my country last year, so I'm looking forward to the opportunity that they're giving me this year. It's going to be a good experience for me to play at my age group."
It remains to be seen if the Wild will take him back after the tournament or send him back to junior. On Tuesday, the Red Deer Rebels of the Western Hockey League traded his junior rights to the powerhouse Portland Winterhawks for forward Presten Kopeck and three draft picks.
Dumba is known as a big hitter who brings speed and skill to the defence.
The team is hoping for more help from the NHL in the form of Toronto Maple Leafs defenceman Morgan Rielly, who would likely play in the top pairing and man the point on the power play.
Rielly has not yet been loaned to the junior team by Toronto, but he's been a healthy scratch recently and the Leafs recalled defenceman John-Michael Liles from the AHL, fuelling speculation that Rielly will end up in Malmo.
Scott Salmond, the team's senior director of hockey operations, said he was told the Leafs would decide by next Tuesday whether to have the fifth overall pick in the 2012 NHL Draft play in the world juniors for a second year in a row.
"We have no concern about him stepping right in and being a leader on our team," said Salmond.
Unlike previous years when more than 30 players were invited to camp, only 25 were called this time. Only three cuts need to be made to get down to the final 22-man squad of two goaltenders, seven defencemen and 13 forwards.
The team will play three pre-tournament games in Sweden — Dec. 20 against Finland, Dec. 22 against Sweden and Dec. 23 against Switzerland.
The Canadian side hopes to have cuts made after the Finland game so the final team is together for the last two exhibition games. But Salmond said they may wait until after the second game.
It is the smallest pre-tournament camp since 26 players were invited in 1983.
It was uncertain if the dazzlingly skilled Drouin, picked third overall by Tampa Bay in the June draft, will be able to skate at camp. But Salmond said the left-winger will accompany the team to Sweden and they hope he will be able to play.
The Halifax Mooseheads star suffered a concussion last week after a hit by Adam Erne of the Quebec Remparts, who is on the U.S. team's world junior preliminary roster.
"He'll be evaluated when he gets here," said Salmond. "We'll follow the protocol.
"If he's symptom-free, he could skate."
Drouin, a member of last year's team that lost in the semifinals to Russia, is expected to play on the top line in Malmo.
Others to watch in camp include tough-to-stop London Knights centre Bo Horvat, quick-footed centre Nic Petan of Portland and Quebec Major Junior Hockey League scoring leader Anthony Mantha of the Val d'Or Foreurs.
But perhaps the most closely watched will be three players yet to be drafted by NHL clubs — 16-year-old sensation Connor McDavid of the Erie Otters, Kootenay Ice forward Sam Reinhart and Barrie Colts defenceman Aaron Ekblad.
Reinhart and Ekblad are potential 2014 first overall picks, while McDavid, who some consider the best prospect since Sidney Crosby, won't be draft eligible until 2015.
Salmond said the youngsters still have things to prove to management in camp, but "being in the mix of 25, they have as good a chance as anyone" of making the team.
Reinhart's older brother, defenceman Griffin Reinhart — the New York Islanders fourth overall pick in 2012 — will be in camp but could give management a tough decision. The skilled, physical blue-liner was suspended for four games at last year's world juniors for slashing U.S. forward Vince Trocheck in the semifinals.
He missed the final last year and is to sit out Canada's first three group stage games of this year's event — against Germany, the Czech Republic and Slovakia. If he's selected, he will be eligible to return for a New Year's Eve game against the Americans.
Every year Canada is without eligible players who were kept by their NHL teams. This year they will be missing Nathan MacKinnon of the Colorado Avalanche, Sean Monahan of the Calgary Flames and Tom Wilson of the Washington Capitals.
But this time several countries will be missing key players, including Seth Jones and Alex Galchenyuk of the United States, Sweden's Filip Forsberg and Hampus Lindholm and Finland's Aleksander Barkov, Olli Maatta and Rasmus Ristolainen.
Russia is without Valeri Nichushkin of the Dallas Stars, but were given Mikhail Grigorenko and Nikita Zadorov by the Buffalo Sabres. Zadorov had already been returned to London.
Canada's team will practise Friday and Sunday at the Mastercard Centre in Toronto and play an exhibition game Saturday against a group of university players, the CIS Toronto Selects.