Car Noise

I have a '98 Saturn with 75,000 miles. Recently I hear a thumping sound between the passenger front door and the front right wheel. It sound like someone threw a ball which hit the car. It’s happened to me three times while driving straight down the street at about 25MPH.

Any ideas?

Turn the wheel all the way to the right and turn off the car. Push on the inside of the wheel well. There are sometimes plastic pieces used to closeout the wheel well, and one might be loose.