Passing comes alphabetically before Running in Callahan's 8000 page playbook. Since Callahan had only 4 years to institute his system instead of the 8 he had forseen, he was only able to get the team through the first 4000 pages of offense and hadn't reached the running plays yet...thus the emphasis was on the pass (and a few running plays recalled from the Solich era)
Unfortunately, the defensive playbook was a whole seperate volume which was misplaced before the year began (Cos claimed that his dog ate it...Callahan was NOT amused, knowing Coz was a "cat person" and didn't even own a dog) so the defensive squad, though well-versed in offensive dogma (such as avoiding contact), never did learn how to properly play defense in the Big 10.