Let me second the person who suggested the 300mm lens...
Shutter speed? I would say keep it above 1/1000th. If it's a daytime game, I would suggest using Aperture Priority mode.
Aperture priority? I guess you suggest that aperture be set to wide open - f/2.8 or whatever to help with AF accuracy. Then pump up ISO enough to keep the shutter 1/1000th or more.
I'm considering buying a used 7D, which will give me the equivalent to 300mm compared to the 5D II. Only thing is probably a bad time to buy a 7D body now but may get one used and just resell it if not happy with it. Thanks again everybody for the advice. Shooting soccer is new to me 
The game is this Sat. 3PM.

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