Summer is the heart of the baseball season. But recently the country’s oldest professional sport has been going through some changes. It’s not just the moves to speed up the pace of play. These days, along with training in the weight room or the bullpen, players are also spending time with their team’s sports psychologist. KQED’s health correspondent April Dembosky goes behind the scenes at the San Francisco Giants’ ballpark to understand how the team keeps an athlete’s mind in shape, both on and off the field.