From the beginning, the character of Lisa Niles was written to be a troublemaker. The producers cast blond, good-looking Julie Mond in the role, that of a doctor and old college flame of Dr. Patrick Drake.
But Mond only played the role from November 18 to to January 5, 2010. The reason? "A change in direction," according to a spokesperson. Brianna Brown was brought in on January 6, 2010. I suspect a stronger actress, or a more overtly sexy one, was wanted in the role - though it would have been interesting perhaps to have someone deceptively nice and sweet in the part as well. Mond did register a quieter kind of energy. Sometimes you just have to see a character in action to realize what would work better.