I fought this problem for quite a while. Try walking out into the pasture (you may have to do this in lieu of riding for a couple of days, don't go out with the intent of accomplishing something else, too), and walk toward your horse. When he responds (Lifts his head and looks at you), immediately stop, turn, and walk away. Keep looking back over your shoulder, and when he goes back to grazing, start walking toward him again. If just approaching him doesn't generate interest, you can try pretending to be sneaky, singing, or anything else, just get his full focus on you as you walk toward him, then walk away with a "never mind" kind of attitude. Eventually, your horse will start turning his shoulders to follow you, even take steps toward you. This method can really play off of his playfulness. When you do catch him, pet him, then release him and walk away. Repeat. Hope that helps!
A stubborn horse walks behind you, an impatient one in front of you, but a noble companion walks beside you ~ Unknown