On June 26, at the 2015 NHL Entry Draft and in his first major move as GM, Sweeney traded restricted free agent defenceman Dougie Hamilton to the Calgary Flames in exchange for the Draft's 15th overall pick (used to select Zachary Senyshyn) and two second-round draft picks. Shortly after, he traded long-time Bruins forward Milan Lucic to the Los Angeles Kings in exchange for the 13th overall pick (used to select Jakub Zbořil), Martin Jones and Colin Miller. Four days later, on June 30, Sweeney then traded Jones to the San Jose Sharks for a first-round pick in 2016 (29th overall, used to select Trent Frederic)