Labrador Hip Problems

I have read quite a bit about how Labradors are prone to hip problems. Well, I was out side today and noticed Gunner wasn't being himself (running, jumping, wanting to play) so I looked him over real good. Nothing seemed out of the ordinary until I noticed how he was walking. I quickly noticed something was wrong with his back end. I checked him over, running my hand over and lightly squeezing his back legs and hips, all the while thinking about how Labradors Retrievers are prone to hip problems. He showed no signs of pain but I know something isn't right. He can barley put weight on his right back leg, guess it's off to the vet in the morning if he doesn't show any improvement by morning. I'm hoping its nothing serious.