The Bruins retained McQuaid, a restricted free agent, with a four-year contract worth $11 million, a league source confirmed to ESPN's Pierre LeBrun.
Sweeney had said Thursday he would "love" to have McQuaid back with the team.
McQuaid, 28, has played six seasons with the Bruins and has been a mainstay on the blue line. Injuries have interfered with his career at times, but the 6-foot-5, 210-pound defenseman has produced when healthy.
He played 63 games last season and had one goal and six assists for seven points.