Normally you would select IDs using the ID selector #, but for more complex matches you can use the attribute-starts-with selector (as a jQuery selector, or as a CSS3 selector):
div[id^="player_"]
If you are able to modify that HTML, however, you should add a class to your player divs then target that class. You'll lose the additional specificity offered by ID selectors anyway, as attribute selectors share the same specificity as class selectors. Plus, just using a class makes things much simpler.