"He'll be out for a little bit, but we don't anticipate it being too, too long," Bruins coach Claude Julien said.
Julien did not say when Hamilton suffered the head injury, but the defenseman did log more than 15 minutes of ice during Saturday's 1-0 win over the San Jose Sharks at SAP Center in San Jose.
He did not play in the waning minutes of that game, but Julien said it was not injury related.
Hamilton has played the past five games after missing the previous 10 due to a knee injury.
Overall, he has four goals and six assists for 10 points, including a plus-9 rating in 33 games for the Bruins this season.