By: Chris Brown (Yahoo Sports) –

Pete Carroll doesn’t want to get burned twice. We all know the most heartbreaking loss of Carroll’s tenure came at the hands of Vince Young’s magnificent performance in the 2006 Rose Bowl, where he dashed USC’s hopes of a three-peat with over 200 yards passing and rushing. Young played an otherworldly game, and it’s quite possible no defense could have stopped him on that stage.

But Carroll knows he didn’t design a very good gameplan for Young, either. In assessing Ohio State’s own duel-threat nightmare, Terrelle Pryor, earlier this week, Carroll lamented facing another Young-esque phenom, but also insinuated that his philosophy toward running quarterbacks has changed:

“Everybody has trouble with them,” Carroll said. “I just think it’s the hardest thing to defend, a running quarterback.”

Carroll said USC’s defensive scheme is more advanced now and that he has learned to “respect the QB position as a threat.”

How well Carroll’s “advanced” approach deals with Pryor’s scrambling ability could be the critical factor in the outcome Saturday night: Sans a string of mistakes by USC’s freshman quarterback, the only realistic scenario for an OSU win is for a breakout out game from its star quarterback, the game we’ve all been waiting for him to play but haven’t seen yet beyond inconsistent flashes.

Adding it up. Against Texas in that historic Rose Bowl, Carroll centered his defense around lining up in a “two-deep shell,” or a defense with two deep safeties to defend against big plays. There was some logic to this: You want to “contain” Vince Young, and a Cover Two look allowed the cornerbacks to play short and aggressive, funneling everything into the middle linebacker and the safeties, who would be there to clean up.

Young thwarted Carroll’s plans by throwing often and accurately in one of the most precise passing performances of his life, completing 30 of 40 attempts on mostly short throws to his slot receiver or tight end in the spaces vacated by the Trojan linebackers preoccupied with Young’s potential to escape. Texas receivers averaged only nine yards per reception, and tight end David Thomas had a career night with 10 catches over the middle, including a few crucial third down conversions.

One of Carroll’s strengths is his ability to adapt. As part of his newfound “respect” for the mobile quarterback, he saw that the problem was not the nature of the blitzes or yelling at guys to keep contain on the outside. Instead, he had a math problem: He needed another guy “in the box” to account for the quarterback as a runner. Fortunately for USC, this was fairly easily accomplished within its usual schemes.

Specifically, Carroll runs a version of the 4-3 defense known as the “under.” He’s been around the under front since at least 1977, when he was a graduate assistant at Arkansas under Lou Holtz (head coach) and Monte Kiffin (defensive coordinator).

The basic idea of the front is that the strongside linebacker rotates down and actually aligns on the line of scrimmage, just outside the tight end. In respect, the defensive linemen shift to the strong side, such that one of the defensive tackles actually lines up as a nose guard over the center, though slightly shaded over. In this coverage Carroll’s safeties, especially the incredible Taylor Mays, are integral because he asks them to be able to play deep coverage and rotate down to play run defense or cover a receiver man-to-man.

USC doesn’t see many offenses designed to exploit a running quarterback on the West Coast, but “under” expert Jerry Gordon explained to me that he expected Carroll’s defense, when presented with a three-receiver, one-tight end, shotgun set, to line up with two deep safeties and rotate one down at the last minute. From this look, Carroll’s favorite coverage has traditionally been Cover 1 — straight man coverage with a deep safety playing centerfield. The interior defenders are assigned to different offensive players, though they will often use what’s called a “banjo” technique, which simply means that two defenders are responsible for two offensive players, and they will take whichever one heads to their side, rather than chase them in either direction……

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