The trick is not to ask for it. Say it with style:
"Excuse me Mr. Manager (or other staff checking how you're doing). How much is a round of golf? Oh ok. Well what if I can't finish it because my foot still hurts from the incident with the glass in the carpet? If I only play half a round, do I have to pay for it all?"
Manager (or staff) usually says "you know what, don't worry about it. Try to enjoy it as it'll be on us."
You "oh are you sure? I don't mind paying for it, just wasn't sure if my foot will..."
Manager "trust me. It costs nothing and we value your money...errr...our customers here. Please enjoy a free round"
You "ok thanks!"