Trim fat from chops. Place chops in a resealable plastic bag set in a shallow dish. For marinade, in a small bowl combine wine, sage, Worcestershire sauce, oil, and garlic. Pour over chops; seal bag. Marinate in the refrigerator for 6 to 24 hours, turning bag occasionally.
Drain veal chops, reserving marinade. Sprinkle chops with freshly ground black pepper. For a charcoal grill, grill chops on the rack of an uncovered grill directly over medium coals to desired doneness, turning and brushing with marinade halfway through cooking. Allow 12 to 14 minutes for medium-rare (145 degree F) and 15 to 17 minutes for medium (160 degree F).
Meanwhile, carefully remove stems from mushrooms; chop stems for another use or discard. Brush mushroom caps with reserved marinade; place mushrooms, stem sides down, on grill rack. Grill for 4 minutes. Turn stem sides up; spoon some pesto into each. Grill about 4 minutes more or until heated through. (For a gas grill, preheat grill. Reduce heat to medium. Place chops, then mushrooms on grill rack over heat. Cover and grill as above.) Serve mushrooms with veal chops. Makes 4 servings.