I've posted this numerous times before, but it's an assertion that still pops up on message boards from time to time. It was a myth in 1997 and it's an infamous myth today: ASU played a prevent defense that led to Rose Bowl defeat and a loss of a national championship.
Prevent defense by a strict definition is three down lineman, two linebackers, and six defensive backs. The down lineman shoot gaps while the linebackers and and DBs drop into a deep zone -- often times what's considered Cover 4, with the safeties and corners dropping way down the field. The theory is there's not enough time left for an offense to drive down the field, so create a scheme that all but eliminates the big play.
As the saying goes, prevent defense prevents you from winning, and I don't necessarily disagree with that.
What ASU used was a mix of man, zone blitz, and zones. They kept four linemen in at all times, and used the safeties in a Cover 2. Was it softer than most of the coverages they'd shown Ohio State all night? Yes. But factors had played into the decision:
- ASU had already been burned twice in good man coverage, once for a touchdown.
- The depth at corner was not good, and Ohio State's bigger, faster receivers had worn out the DBs all night long. They were out of breath.
What ASU employed was not unusual, and it wasn't even new to the defense. They had used some zones and zone blitz all year long. Dropping the backers into a medium net made sense, especially when you're trying to force a QB into throwing too short or too long. It accounted for part of their improved success in most every category that year. It was in fact working against Ohio State, but ASU could not get a stop on third down. Joe Germaine made three very good passes to convert on 3rd down three times on the drive.
The touchdown pass from Germaine to David Boston showed exactly why ASU didn't want to throw a lot of bump coverage into the mix. ASU safeties were playing the deep inside, and freshman CB Courtney Jackson was playing an inside technique. They were taking away the slant. Boston showed inside and Jackson bit, then faded into no-man's land as Boston spun outside and caught a pass without a defender within three yards of him.