To me, that would scream, "I'm having fun playing baseball," which is a good thing. Clearly, he hasn't been good at the plate during the bulk of his short career, but nobody here knows why. Just because he smiles and laughs and has fun doesn't mean he isn't trying to get better. I remember when we had our team picture for the baseball team in high school, I was the only one who smiled. One of my teammates asked me why and said, "You have to take the game seriously." "I do take it seriously," I said. "But I can have fun at the same time." It's all mumbo jumbo. If he never smiled, it would be something about how he's not having fun out there and thinking too much. Sorta like how Aaron Rodgers's grimaces take on new meaning every other year.