At least at first glance, the Cubs seem to have found a solution in center field by signing Jason Heyward to an eight-year contract. Heyward was the prize among the position-player free agents, a three-time Gold Glove Award winner and two-time All-Star who, at 26, presumably has his best years ahead. One potential issue, however, is that much of Heyward’s value is based on his defensive play in right field, a position where he has proven to be among the game’s elite.