So I rented a flute for the summer and I think there`s a slight leak in it. It happened just recently when a sophomore hit my flute with a tennis ball. [it was being thrown around, carelessly as you can imagine.]

Anyways, I`ve been practicing with it and found that my Bb on the staff sounded a little funky. Is it possible that I could have leaks or other problems?

It`s not just possible. It`s highly likely.

Yes, it sound like you do have a leak. I know I had a friend that had the same thing happen to her (except it got hit by a football during a game!) It completly broke one of the post of her flute and she, needless to say, had alot of leaks in it! It should not be diffucult to fix and any good flute repairman (or repairwoman) should be able to fix it with no problem. Hope this helped, shawn