| Week | Rank | Rate | Record | SOS | Opponent | Score | Rank Then | Rank Now |
| 1 | 40 | 0.000 | (0,0) | 0.000 | --bye-- |
| 2 | 29 | 0.500 | (1,0) | -0.500 | Utah St | 24 to 14 | 424 | 103 |
| 3 | 129 | 2.974 | (2,0) | 1.974 | Iowa St | 20 to 13 | 220 | 37 |
| 4 | 50 | 2.002 | (3,0) | 1.002 | Western Michigan | 41 to 10 | 149 | 164 |
| 5 | 44 | 1.823 | (3,1) | 1.323 | Penn State | 0 to 31 | 5 | 11 |
| 6 | 25 | 2.071 | (4,1) | 1.471 | Michigan St | 26 to 16 | 88 | 72 |
| 7 | 14 | 2.230 | (5,1) | 1.564 | Purdue | 20 to 14 | 84 | 83 |
| 8 | 9 | 2.313 | (6,1) | 1.599 | Wisconsin | 15 to 6 | 26 | 53 |
| 9 | 18 | 2.006 | (6,2) | 1.506 | Minnesota | 10 to 12 | 36 | 61 |
| 10 | 20 | 2.043 | (6,2) | 1.543 | --bye-- |
| 11 | 18 | 2.055 | (7,2) | 1.500 | Northwestern | 10 to 7 | 67 | 35 |
| 12 | 15 | 2.126 | (8,2) | 1.526 | Rutgers | 22 to 0 | 41 | 44 |
| 13 | 14 | 2.112 | (9,2) | 1.476 | Illinois | 15 to 13 | 62 | 73 |
| 14 | 13 | 2.190 | (10,2) | 1.524 | Nebraska | 13 to 10 | 81 | 81 |
| 15 | 13 | 2.059 | (10,3) | 1.521 | Michigan | 0 to 26 | 2 | 2 |
| 16 | 13 | 2.056 | (10,3) | 1.517 | --bye-- |
| 17 | 13 | 2.037 | (10,3) | 1.498 | --bye-- |
| 18 | 16 | 1.955 | (10,4) | 1.526 | Tennessee | 0 to 35 | 20 | 20 |
| 19 | | | | | --bye-- |
| 20 | | | | | --bye-- |