For years the Dolphins were an offensive showcase. Of course a weapon such as Hall of Fame quarterback Dan Marino can be hard for a coach to ignore. Jimmy Johnson, though, never lost sight of his primary pledge to improve the team's defense. Mission accomplished. The Dolphins now possess one of the best defenses in the league. No defender better personifies the team's newly stingy soul than linebacker Zach Thomas. Since joining the Dolphins as an unheralded rookie two seasons ago, he has emerged as all-NFL, all-Madden, and all-important to a team that still hasn't won the Super Bowl Johnson promised three years ago. Management recently rewarded Thomas with a five-year, $22.5 million contract. Some of that money will replace the cash the player lost in January when he was mugged in New York City. Considering Thomas's imposing build, the bandit who blindsided him (he suffered bruises and needed five stitches in his lip) must be an all-pro in the criminal community. Best Moxie by a Mugger?