If I remember correctly, Heupel had a hard time hiring a DC. He was trying to recruit and get his staff together and was getting turned down by DC candidates. Before he hired Banks, he retained Garner then brought Willie with him. While Banks was somewhat successful, he was not Heupel's 1st choice. Other programs have not adopted Heupel fast paced offense and other have adapted to it. Heupel is smart in not getting a great DC and turning the defense over to him. The only way to hold Knowles accountable is allow him to select his staff and therefore his players. This should also allow Heupel to concentrate more of his time on the offensive side while still being the CEO of the program.