| Week | Rank | Rate | Record | SOS | Opponent | Score | Rank Then | Rank Now |
| 0 | 9 | 0.000 | (0,0) | 0.000 | --bye-- |
| 1 | 7 | 0.500 | (1,0) | -0.500 | New Mexico | 34 to 17 | 518 | 51 |
| 2 | 587 | -0.828 | (1,1) | -0.828 | Oklahoma | 13 to 24 | 319 | 8 |
| 3 | 134 | 0.977 | (2,1) | 0.643 | C Michigan | 63 to 3 | 408 | 132 |
| 4 | 28 | 1.853 | (3,1) | 1.353 | Nebraska | 30 to 27 | 77 | 55 |
| 5 | 11 | 2.246 | (3,1) | 1.746 | --bye-- |
| 6 | 14 | 2.113 | (4,1) | 1.513 | Wisconsin | 24 to 10 | 94 | 59 |
| 7 | 34 | 1.821 | (4,2) | 1.488 | USC | 13 to 31 | 18 | 14 |
| 8 | 22 | 1.962 | (5,2) | 1.533 | Washington | 24 to 7 | 23 | 23 |
| 9 | 17 | 2.065 | (6,2) | 1.565 | Michigan St | 31 to 20 | 88 | 89 |
| 10 | 14 | 2.068 | (7,2) | 1.512 | Purdue | 21 to 16 | 121 | 111 |
| 11 | 12 | 2.097 | (7,2) | 1.542 | --bye-- |
| 12 | 12 | 2.170 | (8,2) | 1.570 | Northwestern | 24 to 22 | 56 | 48 |
| 13 | 11 | 2.165 | (9,2) | 1.529 | Maryland | 45 to 20 | 99 | 114 |
| 14 | 12 | 2.072 | (9,3) | 1.572 | Ohio St | 9 to 27 | 1 | 4 |
| 15 | 13 | 2.080 | (9,3) | 1.580 | --bye-- |
| 16 | 13 | 2.087 | (9,3) | 1.587 | --bye-- |
| 17 | 14 | 2.090 | (9,3) | 1.590 | --bye-- |
| 18 | 13 | 2.094 | (9,3) | 1.594 | --bye-- |
| 19 | 18 | 1.984 | (9,4) | 1.599 | Texas | 27 to 41 | 17 | 17 |
| 20 | | | | | --bye-- |
| 21 | | | | | --bye-- |