The reason this is a problem is because of the fact that a baseball player, whether a pitcher or hitter, doesn’t use this energy system. Baseball athletes use the ATP energy system, which can provide energy for movements up to 10 seconds. A pitch or swing is a very short, explosive movement that is followed by a 10-20 second rest before the movement is repeated. This is far different than a continuous movement for many minutes at a time. Consequently, if a pitcher or hitter wants to increase their explosiveness, whether it is to increase the velocity on his fastball or improve his bat speed, he will need to train to be explosive through short explosive movements.
Perhaps the best way to put it in perspective, a 100 meter sprinter does not train by running long distances. Instead, that sprinter works on running short distances, such as training to be as explosive as possible off the blocks. In the same regard, a baseball athlete is not going to be helping himself by training for long periods of time in order to be more explosive.
By simply performing a random selection of exercises that don’t require any type of rotational movement, a baseball athlete is not preparing himself for the stress that those rotational movements will create on his body. In particular, a baseball athlete needs to specifically address thoracic spine and hip mobility as well as anti-rotation core stability. Crossfit does not address these sport specific concerns.