BOSTON -- United States defenseman Charlie McAvoy will miss the 4 Nations Face-Off championship game Thursday between the U.S. and Canada.

The Boston Bruins said in a statement Tuesday that McAvoy was admitted to Massachusetts General Hospital on Monday to undergo testing related to an upper-body injury. McAvoy sustained the injury during the 4 Nations Face-Off and is currently being evaluated by Bruins head team physician Dr. Peter Asnis.

Reigning Norris Trophy winner Quinn Hughes will join Team USA ahead of the championship game, Team USA and Pittsburgh Penguins coach Mike Sullivan announced. Per tournament rules, Hughes, who is the older brother of Team USA and New Jersey Devils center Jack Hughes, would only be eligible to play if there is another injury on Team USA's defense.

Sullivan, who is McAvoy's father-in-law, said during his news conference that McAvoy's injury is a "tough" loss, but it would only increase the demand for others in the lineup to step up.

"He's played extremely well through this tournament," Sullivan said. "When you lose players of his caliber, they're not easy to replace. I know from a personal standpoint what this tournament's meant to him and how much he was looking forward to playing in this. Having said that, we have capable of people. We have a lot of depth at all positions and it's going to provide opportunities for others to step up."

Hughes, who has 14 goals and 59 points for the Vancouver Canucks, while averaging more than 25:18 in ice time this season, initially made Team USA's roster but had to back out because of an oblique injury.

Canada utilized the injury replacement player protocol earlier in the tournament when it called up Dallas Stars defenseman Thomas Harley. Harley was eligible to play for Canada after it lost Vegas Golden Knights defenseman Shea Theodore for the remainder of the tournament in addition to Colorado Avalanche defenseman Cale Makar missing the first game against the U.S. due to illness.

"It's probably good for the game. No doubt about that. Quinn Hughes is a special player," Canada coach Jon Cooper said. "It was unfortunate he was hurt to begin with."

Cooper confirmed that the only way an injury replacement player can join the lineup is if a team is at risk of playing short-handed, meaning that the Americans would need one of their six remaining defensemen to be unavailable against Canada for Hughes to play.

Team USA and Golden Knights defenseman Noah Hanifin has known McAvoy for years. They were part of the United States National Team Development Program at the same time as future Team USA teammates such as Jack Eichel, Dylan Larkin, Matthew Tkachuk and Zach Werenski.

"There's a lot of things [Team USA will miss]. His character, the way he is in the room, his leadership," Hanifin said. "He's just such a phenomenal teammate. The physicality he brings to the team and how hard he plays with each shift. That's contagious for any group he's a part of and we're going to miss that a lot on Thursday."

McAvoy was held out of the United States' 2-1 loss to Sweden on Monday at TD Garden in Boston. The U.S. had already qualified for the championship game having won in regulation against Finland to open the tournament before beating rival Canada in its second game.

The 27-year-old was one of a few players who missed what was essentially an inconsequential game against Sweden. It's a group that also included Toronto Maple Leafs forward Auston Matthews and Florida Panthers forward Matthew Tkachuk, who missed the Sweden game out of injury precautionary.

The U.S. played New York Rangers forward Chris Kreider and Ottawa Senators defenseman Jake Sanderson in a game that also witnessed forward Brady Tkachuk get hurt in the first period with a lower-body injury. He returned for a 14-second shift in the first period but would later be ruled out.

Sullivan said he anticipates Matthews being available for the championship game. ESPN's Emily Kaplan is reporting that the Tkachuk brothers will also play Thursday.

ESPN's Greg Wyshynski contributed to this report.