The 4 Nations Face-Off is down to the championship game Thursday (8 p.m. ET, ESPN) between the United States and Canada.

The USA has been dealing with injury issues, with defenseman Charlie McAvoy out of the tournament with a significant shoulder injury. Auston Matthews and Matthew Tkachuk also missed Monday’s game and Brady Tkachuk left early, though they’re expected to be good to go.

The Athletic’s Pierre LeBrun reported that Vancouver Canucks defenseman Quinn Hughes won’t be coming to Boston as a potential replacement because he hasn’t been medically cleared from his injury.

Buffalo Sabres forward Tage Thompson and New Jersey Devils defenseman Brett Pesce will be brought in as potential replacements, according to a person with knowledge of the situation. The person spoke to USA TODAY Sports on the condition of anonymity because the decision hasn’t been announced.

Here are the tournament rules on injury replacements and the overtime rule for the final:

What is the injury replacement rule for 4 Nations Face-Off?

NHL deputy commissioner Bill Daly told USA TODAY by email that an emergency replacement on defense can play “only in the event Team USA has an injury emergency prior to (the) game on Thursday that leaves them at below six healthy defensemen.”

In other words, if another U.S. defenseman besides McAvoy is ill or injured and can’t play, then an emergency replacement can suit up. Two forwards would have to be unavailable in order for Thompson to play.

Here is the wording on the rule:

“Teams that, by reason of injury, drop below six able-body defensemen, 12 able-body forwards or three able-body goaltenders will be permitted to apply for emergency relief in the form of identifying and adding to their roster additional injury replacement player(s) on an ‘as needed’ basis only. Applications for injury relief will be ruled on by the Chairpersons of the Tournament Directorate (Bill Daly and Rob Zepp), and will be final when made.

“The roster limitations do not impact the ability of teams to identify potential injury replacement players in advance of the actual emergency. Identified and willing player(s), however, will not be added to the roster, nor will they be permitted to participate in any team activities, prior to being approved as injury replacement players. Once an injury replacement player has been approved and added to a team, he will be permitted to practice and participate with his team on an unrestricted basis (practice and/or game) for the balance of the tournament, regardless of whether his team remains in an emergency situation.”

Canada had a similar situation earlier in the tournament when defenseman Shea Theodore was hurt in the opening game. The Canadians brought in Thomas Harley as an emergency replacement. He was able to play in the USA game because Cale Makar sat out with an illness.

4 Nations Face-Off overtime rules

During the round robin, overtime was 10 minutes of sudden death 3-on-3 play, as opposed to five minutes for the NHL regular season. Canada and Sweden played more than six minutes before Mitch Marner scored for the Canadians.

In the championship game, though, overtime will be the same as in the NHL playoffs: Teams will play 20-minute periods of 5-on-5 play until someone scores.