That would surely be my guess. Without knowing what brand of tire you have, or whether this is the front or rear tire, if you see something that's out of the norm, it surely needs to be checked out. The rear tire will wear more quickly than the front, and the rear tire usually begins to get a wider and wider flat spot in the center of the tire as it wears. There's not as much weight on the front, so it can last a long time. Many people that don't rotate their tires will replace the rear tire 3 to 5 times before the front tire needs attention. Inspect the entire tire carefully to see if you can find any of the carcass material beginning to show through. If so, you need to begin shopping for a tire.