Answer

Hi Johnny,

You are right.  The fans often don't see the Major League players warm up before the game, but believe me, they do.  Most of the time, each team arrives at the field 3 hours before the scheduled start.  The home team warms up on the field first for about an hour, and then the visiting team gets a turn for about an hour.  Most of the time is spent taking batting practice, while the postion players take ground ball or fly balls in the field.  After all of the players get to hit and properly warm up, they go inside to the clubhouse to get something to eat and change uniforms for the game.

Here is a video of Albert Pujoles taking batting practice before the game: