ATLANTA — The Atlanta Thrashers signed free agent defenseman Ron Hainsey on Wednesday, adding size and youth to their blue line.

General manager Don Waddell said the 27-year-old Hainsey “is now entering the prime of his career.”

“Ron is one of the best young defensemen in free agency and we’re very happy to be adding a player of his caliber to our lineup,” Waddell said.

“He moves the puck well, has good offensive capabilities and is a solid all-around defenseman who has taken significant strides with his game over the last few seasons.”

Hainsey was a first-round pick by Montreal in 2000. He spent the last three years with Columbus and had eight goals — all on the power play — and 24 assists last season. Hainsey is expected to give the Thrashers’ power play a boost. He ranked sixth among NHL defensemen in power plays.

Hainsey, who will earn $22.5 million in the five-year deal, becomes the Thrashers’ highest-paid defenseman.

The 6-foot-3, 211-pound Hainsey made his NHL debut with Montreal in 2002. He was the 13th overall pick in the 2000 draft.

He has 85 points (20 goals, 65 assists) in 245 career games. He set a career high with 34 points for Columbus in the 2006-07 season.