Preheat an outdoor grill for medium-high heat. Lightly oil grill grate, and place about 4 inches from heat source.
Mix the ground sirloin, garlic, onion powder, Gorgonzola cheese, and basil together in a large bowl until evenly blended. Divide mixture evenly to form four patties.
Cook patties on preheated grill until meat is evenly browned and center is no longer pink, about 5 minutes on each side.
