It's possible he's just bored--if he still looks bright and vibrant as usual he's probably fine. To satisfy your concern, you should darken the room and shine a flashlight on him. Sometimes velvet can be hard to spot in normal light--look for gold-yellow granules in between the scales. You should also test your water to make sure your maintenance regime is adequate, since ammonia can make the fish uncomfortable, which can cause some erratic behavior as well.
If everything checks out as fine, you should find some way to help relieve his boredom, such as rearranging tank decor, adding more decor, and/or arranging colorful interesting objects around his tank for him to look at.