The Dolphins have signed Larry Johnson as insurance at the running back position. Johnson knows he must quickly make a good impression, including off the field, where repeated missteps derailed his career. "It's kind of hard to convince anybody with my colorful background that, yeah, I've changed," said Johnson. "But you change with every situation you go through. You know that you can't get many more shots. You do the best you can with your opportunity and ride on out to the sunset."