...Although, with a 600, you'll be able to take interesting images of the goal area... from the opposite one!
Depending on your location (on the pitch by the side line or on the stands) you'll need shorter or longer lenses, but the usual range is something between 200 and 400. My favorite lens for soccer is the 300 2.8, but shorter lenses can be used for closer action when 300 becomes too long. As you won't have time to change lenses, it is better to carry two bodies.
Fast lenses are also a must for nighttime games. Lenses slower than f4 become unusable by night, since you need to freeze action (shutter speed of 1/400 or faster...)
--
http://www.felipe-rodriguez.com
Bokeh
Dadme un mundo sin contornos,
Un espacio feliz que ignore los perfiles.
Concededme, sí, la dicha redonda
De flotar sin conciencia en el fondo
Desenfocado de mis fotografías.
Give me a world with no edges,
A happy space knowing nothing about outlines.
Grant me, please, the round joy
Of thoughtlessly floating on the blurred
Background of my photographs.