Do you want to freeze the motion of the ball and bat, or do you want a little motion blur to imply action? Either way, I would start by selecting a shutter speed for the task, and a good overall aperture (f/8?) to get the DoF you want. Then mess with ISO if need be. You probably want to shoot in manual mode. The second image seems to have better exposure balance between the dark shirt and the white pants - also, because of the position of the sun, the white pants fall into shadow during the swing (like in image 2 especially) - so you can expose for the shirt if there is shadow detail you want to preserve and the white pants won't completely blow out - if you shoot raw, you can also recover the white pants easier with the highlight data - if you block your shadows you have limited ability to recover them. You definitely do not want to lose all of the highlight data in the ball or the arms/skin so not too heavy on exposing for the shirt.
Have fun!
Kirk