Lynden Dunn will be asked to fill a key need for Collingwood in defence in 2017 after the veteran backman was traded from Melbourne. 

The 29-year-old has been swapped along with the Demons' pick 51 for Collingwood's pick 47.

Dunn, a former vice-captain at Melbourne, managed just four senior games in 2016 as the Demons preferred to get games into Oscar McDonald and Sam Frost. 

Both Dunn and the Demons were happy for the veteran to explore his options in the trade period and the Magpies appear to be a suitable option after losing Jack Frost and Nathan Brown to the Brisbane Lions and St Kilda respectively. 

Demons football manger Josh Mahoney said Dunn leaves the club with its best wishes. 

"The reason this trade eventuated was due to our end of year discussions, where Lynden's management came to the club seeking clarification on his future, after having limited opportunities in 2016," Mahoney said.

"Following on from those discussions, Lynden was keen to pursue his options and continue his career at another AFL club.

"When an opportunity presented to join Collingwood during this trade period, we were happy to facilitate that opportunity for Lynden, who will continue his career there."

The 29-year-old played 165 matches for Melbourne from 2006-16, after being drafted at pick No.15 in the 2004 NAB AFL Draft.