At the 1998 Commonwealth Games, Roberts achieved a gold medal for the Teams Pursuit, a silver medal in the Individual Pursuit, and came 8th in the Points race. Four year later at the 2002 Commonwealth Games in Manchester, Roberts won gold in the Teams Pursuit and 4th in the Individual Pursuit. His 2010 road racing team, Team Milram, folded at the end of that season, and he signed to ride for a proposed Australian team known as Pegasus: this team, however, failed to obtain a UCI license. After riding with UniSA in the 2011 Tour Down Under, Roberts signed with Saxo Bank–SunGard, a continuation of the squad he was with from 2005–2007, for the remainder of the season.