TSN is reporting the Boston Bruins , who recently signed defenseman Johnny Boychuk to a contract extension, are working on new deals for four forwards to keep them off the free-agent market.According to the report, the team has approached centers Chris Kelly and Gregory Campbell , left wing Daniel Paille and right wing Shawn Thornton with offers that would keep them from becoming unrestricted free agents July 1.All four played major roles in the Bruins' 2011 Stanley Cup championship.Kelly, acquired from the Ottawa Senators at the trade deadline last season, has 14 goals, 12 assists, a plus-25 rating and in 55 games this season, and has won 55.2-percent of his faceoffs.Campbell, Thornton and Paille make up the Bruins' fourth line -- nicknamed the "Merlot Line" by Thornton due to the maroon-colored practice jerseys they wear.Campbell has six goals and seven assists in 52 games, Thornton has four goals, seven assists and a team-high 117 penalty minutes in 55 games, and Paille has nine goals and five assists in 51 games.Earlier this week, the Bruins signed Boychuk to a three-year, $10.1 million deal that prevented him from becoming a free agent.Along with the four forwards, the Bruins' only other prospective unrestricted free agent is defenseman Joe Corvo