The Bruins acquired the rights to the offensive-minded defenseman from St. Louis on June 26 for Vladimir Sobotka. Warsofsky attended the team's development camp last summer.
Warsofsky scored seven goals and 15 assists in 34 games for BU this season. As a freshman, Warsofsky was a member of BU's national championship team. The following year, Warsofsky helped lead Team USA to gold in the World Junior Championship.
The 20-year-old Warsofsky should start 2011-12 in Providence.