For sports you need to use a fast shutter speed, most of the time. To capture the action you must freeze the action. To freeze action I try to use a shutter speed of at least 1/500 of a second for youth sports, but 1/1000 or above whenever I can. If you are shooting a night game or indoors this means you'll need to use a high ISO. You can't use the photo if its blurry so you may as well crank up the ISO and deal with the noise it creates.
Of course rules are made to be broken and it can be fun to use a slower shutter speed, but if you are going to do this then you should use something like 1/25 or slower depending of the subject. You won't get many useful photos, but if you do it'll be interesting and different from a standard peak action shot.