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.