Campbell, the Bruins' fourth-line centre, broke his right leg in the second period of Boston's double-overtime win in Game 3 on Wednesday night. He is out for the rest of the playoffs.
Daugavins played in just one of Boston's first 15 post-season games this year.
Boston claimed Daugavins off waivers from the Ottawa Senators on March 27. He had no goals and one assist in six regular-season games with the Bruins after posting one goal and two assists in 19 games with the Senators.
Campbell had three goals and four assists in 15 playoff games.
I don't think it's really truly going to sink in until we drop the puck, to be honest. I know there's going to be a lot of smoke and mirrors with the media attention and all that. We came [Monday] and it was sort of a light day to get things organized. We just want to focus in on the business aspect, the game itself. That's what we're preparing to do. Get these next couple of days out of the way and it's game on.
— Lightning captain Steven Stamkos on playing in his first Stanley Cup Final