Goalkeeper Duncan Roberts played for Norwich's youth sides in the mid-1990s, especially the Under-16s in 1994/95. Norwich did not take him on and he joined Mansfield. He was poised to make his league debut for the Stags against Cambridge United when he dislocated a shoulder in training the day before the game.

Returning to Norfolk, he joined King's Lynn. He had the option of following manager peter Morris to Kettering but opted to stay at The Walks with new manager Gary Mills. Sent off in first game under Mills' stewardship, he lost his place to Morrocan international Chuck Martini and so signed for hometown club Wisbech where he won two Player of the Year awards. A spell with Spalding was followed by another stint with the Fenmen. In the autumn of 2001, he joined Ryman Leaguers Harrow Borough. He moved to St Albans in August 2002 but by Christmas 2002, he had joined Bedford Town.

In March 2003, Duncan had a trial with Oldham Athletic, playing for their reserves on 10th March in a Manchester Senior Cup semi-final against Manchester City. Duncan kept a clean sheet as Athletic won 1-0. Duncan obviously impressed Oldham manager Iain Dowie who signed him on non-contract terms on March 25th 2003 until the end of the season. However he was released on May 16th 2003. Duncan spent much of the 2003 summer trainign with Luton and was expected to sign for the Hatters but a transfer embargo was imposed on the Kenilworth Road team.

Despite signing for troubled Welsh side Barry Town, his registration had not been submitted to the necessary authorities .Duncan then signed for Dr Martens League side Newport and made his debut on Wednesday 18th September 2003 against Weymouth. Barnet also expressed an interest.

In May 2004, Duncan signed for Cambridge City, managed by his namesake Gary Roberts (who had also managed him at St Albans City). King's Lynn had also expressed an interest in signing him but the Lilywhites got there first

Duncan left Cambridge City in July 2005 to start up a business in South Wales. He joined Llanelli on trial.