Researchers and scientists at the University of Electro-Communications in Tokyo and the Okinawa Institute of Science and Technology have built a robot with quite the sports prowess, although you probably won't see it take the field anytime soon. The robot is able to swing and hit at plastic balls, and can improve its swing over time.
The robot only stands a couple feet tall, and it uses a giant flyswatter-like bat in order to make contact with the ball, so it essentially can't hit like Alex Rodriguez, but maybe in the future the robot will give the all-star a run for his money. The robot features an artificial brain with the power of 100,000 neurons that allow the robot to learn and improve on its swing over time.
How the whole thing works is that when a ball is pitched to the robot, an accelerometer behind the robot records information about the flight and speed of the ball, and this data is sent to a separate machine off to the side that holds the robot's brain. The data gets processed and it lets the robot know when to swing.
The impressive part is that if the speed of the ball changes, the robot can re-learn the swing all over again to try and hit the ball at the new speed. Hopefully the researchers will be able to soon give the robot a real bat instead of a giant flyswatter and be able to hit real baseballs, but that kind of technology probably won't be on its way for several more years.