scorecenter doesn't allow you to customize the notifications. it doesn't even have a "notifications" preferences item. it just has "alerts"(completely separate from Preferences) where you pick which teams you want to be alerted on. all alerts are the same. it's all or nothing. apparently i must be a crazy person for wanting to see a notification in the notification bar without hearing the sportscenter jingle.
the only thing i can think to do (on a rooted device) is to find and rename the sound file that scorecenter is calling. but so far i haven't been able to find any .wav or .ogg files that have espn, sportscenter, or scorecenter in their names.