Seventh in a series by staff writer Gerry Fraley ranking the top players in Rangers history at each position. Evaluations are based only on performance while with the Rangers.Today, the utility men.Dave RobertsWith Rangers: 1979-80Lasting accomplishment: Only player in club history to start at catcher and center field in the same seasonAcquired from San Diego in the Oscar Gamble trade, Roberts started at seven positions in his time with the club.