there are many reasons as to why the catcher has to be behind home plate and NOT play the infield or out field here are a few ...
the catcher gives the signs to the pitcher ( what to throw)
if theres no catcher the 3rd strike will be dropped ( the batter will take 1st easily)
the cather will frame the ball ( make it look like a strike)
Clarification:
Actually the only fundamental reason you need a catcher behind the plate is --- if you do not, then nobody will be in the "catcher box" and this will be a balk on the catcher, meaning you pitcher can never throw a strike because every pitch will be illegal --- other then that you would probably really upset the Home Plate umpire. I guess if you wanted absolutely no chance of winning (because your pitcher cant get anyone out if every pitch is illegal), then you can stick your catcher wherever you want --- all the other things mentioned above is good too, but those are not THE REASON you cannot have a catcher, because even if your catcher doesnt do those things when he is behind the plate your team will be ok (i.e little league catchers dont do most those things)
There is more than just one reason that the catcher calls the game. One reason is that most of the time the catcher is more familiar with the opposing hitters. Since the catcher is also aware of what pitches are working that day for his pitcher, it makes more sense for him to call for pitches that will keep the opposing hitters of balance. Many times the pitches are signalled in to the catcher from either his manager or pitching coach. This allows the pitcher to consentrate only on what his catcher is calling.
Jose Molina
is He's = He is
Some catchers are allowed more leeway to call pitches by their managers than others. But usually pitches are called by the manager or pitching coach and relayed to the pitcher by the catcher.
A catcher tells the pitcher what kinds of pitches to throw. Also, if the pitcher throws a bad pitch, the catcher can prevent the keep the ball close to prevent any base runner advancements.
The catcher's mask was created in the 1870s by Fred Thayer, a Harvard baseball player. Thayer was concerned about catcher's safety and designed the mask to protect against foul balls and wild pitches.
The catcher because they call the pitches and make lots of the decisions
As a percent your grade is 94% which would be an A in my classes. If you are a baeball catcher and miss 1 out of every 17 pitches, I would look for a new catcher.
no dead ball
You start running when the pitcher pitches the ball and then you make it to the bag before the catcher can throw it to the base you are trying to steal.
Pitches
One of the Giants' major rivals, outfielder Matt Kemp of the Los Angeles Dodgers, was once asked which pitcher in baseball he feared most. His response: "Lincecum. He's got that fastball, curve and nasty [changeup]." The hard-throwing right hander also has a slider and a four-seam fastball in his repertoire of pitches.