Of all the good things Bret Bielema has done as football coach at the University of Wisconsin ? replacing a legend, recovering from the troublesome 2008 season, pushing the program to a new level the past two seasons ? nothing compares in degree of difficulty to task he now faces. And, no, I don?t mean beating Oregon in the Rose Bowl. For his next act, Bielema must replace offensive coordinator Paul Chryst, the home-grown kid who is the unsung hero of UW football in the post-Barry Alvarez era.