Field Size

[Hampe]

Is there any difference between the USA amateur and professional fields?

[Mykal]

there shouldnt be,
NCAA & NFL Both play on the same size field

EDIT - Here's a couple of diagrams from Sports_KnowHow.com

[Hampe]

Oh yea.....I forgot that the hash marks are different.


Small change, but can have a big influence on gameplay I suppose.

[dreamtheatervt]

It doesn't effect video game football as much, but the numbers are also located closer to the sideline, even though its not shown in the above diagram.  It really only effects substitution, but its there.  That's why you will see hashes on the field for where the numbers would be for the other field.

[Marauders]

As I recall, the numbers and the goal post width used to be different but were changed to the NFL standard a few years ago.  The hash marks are the only difference left (wider on NCAA field).

[dreamtheatervt]

The numbers must be different in high school then.  They always bring it up when they play the Hall of Fame Game at Fawcett Stadium in Canton.  If you look at the picture in this link (too big to embed picture), you can see the hash marks for where the numbers are on a professional field.

[Marauders]

The numbers must be different in high school then.  They always bring it up when they play the Hall of Fame Game at Fawcett Stadium in Canton.

 
Yes, the numbers for the NFL field are different as well.
 
High school fields have a wider goal post and wider hash marks, but the distance from the sideline to the top of the numbers is nine yards, as it is in the NCAA.
 
The tops of the NFL numbers are 14 yards from the sideline (12 yards to the bottom with 2 yard tall numbers).
 
 

[Marauders]

By the way, that SportsKnowHow.com graphic posted by Mykal above isn't correct on the pro field numbers.  It doesn't make a difference in the game, but it is just a heads up.
 
On a side note, having both teams on the same side of the field is still allowed under rule.  It is even still allowed in the NFL, although no stadium has had both teams on the same side of the field since the Minnesota Vikings left the Met and the Green Bay Packers stopped playing some of their home games in County Stadium in Milwaukee.