 His professional career started in 1975 when he was signed as a 17-year-old underage junior by the WHA New England Whalers.He represented the Whalers in the 1977 and 1978 WHA All-Star Game and was still with New England when the NHL and WHA merged in 1979.In 1980, the Whalers traded Roberts to the Minnesota North Stars for Mike Fidler.