I have the same problem with that also. I play High School Varsity Baseball.
This explanation will be a little confusing so try to visualize this. Pull your pants up just below the top of your socks. Then grab the waistband and pull your pants down as if you were taking them off and they were going to be inside out. Leave the elastic bottom of the pants around the top of your calf. You will see that your socks are just higher than the bottom of your pants. Now you can fold the sock over the bottom of your pant bottoms. After you fold the sock over the pants, pull your pants back on and buckle up.
The sock folded over the pant bottoms should hold the pants up for the whole game.