for reference, here's what some other B12/big 10 coaches (who have coached the same team in the same conference since at least 2011) have done in the same span:
Bill: 7-10 vs ranked, 31-3 vs unranked, 38-13 overall
Briles 9-6 vs ranked, 31-5 vs unranked, 40-11 overall
Stoops 9-9 vs ranked, 30-3 vs unranked, 39-12 overall
Gundy 10-10 vs ranked, 26-5 vs unranked, 36-15 overall
Rhoads 3-17 vs ranked, 14-16 vs unranked, 17-33 overall
Bo: 3-10 vs ranked, 34-5 vs unranked, 37-15 overall
Kill: 2-11 vs ranked, 23-14 vs unranked, 25-25 overall
D'Antonio: 8-9 vs ranked, 33-3 vs unranked, 41-12 overall
Ferentz: 1-9 vs ranked, 25-15 vs unranked, 26-24 overall
Fitzgerald: 3-6 vs ranked, 23-18 vs unkranked, 26-24 overall
amazing how shitty the big 10 is. for example in 2012, Northwestern did not play a single ranked team (including their bowl game!)