Kelly's deal is for four years for a toal of $12 million while Campbell has a three-year deal worth $4.8 million.
In his first full season with the Bruins last season, Kelly scored 20 goals and added 19 assists for 39 points in 82 games. He was acquired from the Ottawa Senators in February of 2011.
Campbell scored eight goals and eight assists for 16 points in 78 games last season. He was acquired from the Florida Panthers in June of 2010.