Strider makes excellent points about being careful without a ball spinner to change the surface of the ball, but done right it doesn't hurt the ball.
You could also try slowing your speed and moving your feet to change your line a little bit. But you'll have to experiment and it might take a lot of time on league night to figure out just where and how fast to throw so sanding your ball might be more of what you're looking for.
Whenever I go out to bowl for fun (not in a league) at a certain alley, they have so much oil down to protect the lanes that it's hard to adjust initially. But I think moving to the right (for a right-hander) and slowing down your ball speed will help you out, especially if you wipe the oil off your ball every time it comes back. This will help you burn a line in the oil pattern where you want to throw your ball.
