BOSTON -- The Boston Bruins allowed defenseman Bryan Berard to become a free agent Tuesday by rejecting the $2.51 million salary set by an arbitrator last week.

The Bruins are the only NHL team that has ever exercised "walkaway" rights, and they have done so twice. Boston allowed Dmitri Khristich to become a free agent after an arbitrator set his salary at $2.8 million in 1998; he signed with the Toronto Maple Leafs.

The unusual tactic, which gives a team the ability to reject a limited number of arbitrator's decisions, was negotiated as part of the collective bargaining agreement that ended the 1994-95 lockout.

Berard, 26, had 10 goals and 28 assists last year while earning $850,000.

General manager Mike O'Connell said he wants Berard back for less than the salary set by the arbitrator. The Bruins retain the right to match a contract that is less than 80 percent of $2.51 million, or $2,008,000.

"We worked very hard to reach agreement on a contract with Bryan prior to the hearing, and when we could not, I made Bryan aware of what our strategy would be in trying to gauge the current NHL marketplace," O'Connell said. "While there is some risk involved, we are hopeful that we will be able to retain Bryan at a salary that better fits that marketplace."

Also Tuesday, the Bruins accepted the arbitration figure for forward Brian Rolston, who was awarded a $3.175 million one-year salary last week. Rolston had 27 goals and 32 assists last year for the Bruins.

The Bruins also signed unrestricted free agent forward Sandy McCarthy to a one-year deal. It will be McCarthy's 11th NHL season and his sixth NHL team. He had six goals, nine assists and 81 penalty minutes last season with the New York Rangers.