Stanford began 2015 rebuilding its defense. As the season progressed, however, the Cardinal changed the plan. It stopped the meticulous process of rebuilding, picked up its hammers, lumber and architectural designs and instead employed them to relentlessly pound the collective noggins of opposing offenses.

Just ask Colorado, which scored a touchdown on its first possession last Saturday but managed only three more points in a 42-10 defeat.

"They are the most physical football team we will play this year, or I think we’ve played since I’ve been here, by far," Buffaloes coach Mike MacIntyre said.

Stanford not only lost eight starters from its 2014 defense, which was by far the best unit in the Pac-12, it lost pretty much all of its star power, as those loses included three All-Pac-12 players and three others who earned honorable mention. The conventional wisdom in the preseason was that the Cardinal's veteran offense would need to carry things. That has been the case at times, most notably during a 41-31 win over USC on Sept. 19.

Yet here Stanford is after nine games, a College Football Playoff contender, holding up its end of its annual Irresistible Force versus Immovable Object matchup with Oregon on Saturday.

“The kids believe we should be good," defensive coordinator Lance Anderson said. "There’s that culture, that standard that previous years' defenses set.”

Stanford ranks second in the Pac-12 in scoring defense (20.2 points per game) and it it tied for first in scoring D in Pac-12 games (22.7 ppg). It's yielded 5.08 yards per play, which ranks second in the conference, and it ranks first in third-down conversion percentage and second in red-zone touchdown percentage.

Linebacker Blake Martinez leads the Pac-12 in tackles per game, most of those being of the thumping variety. David Zalubowski/AP

Those, by the way, are the stats that really matter.

Yet Stanford also has been dominating without the gaudy defensive jewelry that often gets priority. The Cardinal ranks 11th in the conference in sacks and turnovers forced per game and is 10th in tackles for a loss.

Two weeks ago, explaining the lack of big defensive plays -- sacks and turnovers -- Anderson told ESPN.com's David Lombardi, "Not having the same kind of depth up front has limited some of the blitzes and stunts there. What we ran in the past, we haven't been able to do with the lack of depth and experience."

In wins over Washington State and Colorado, the Cardinal piled up seven sacks and four interceptions. Against the Buffs, Stanford also made eight total tackles for a loss, dominating at the point of attack. So that's clearly an advancement, with Anderson becoming more confident that his defense can increase its schematic inventory.

Stanford's bell cow is linebacker Blake Martinez, who should be in the mix for conference Defensive Player of the Year. Despite Stanford only defending 600 plays -- by far the fewest in the Pac-12 -- he leads the conference with 10.4 tackles per game.

“He’s as good as anyone who has played for us over the last few years," Anderson said. "Extremely productive. He’s such a strong, physical kid. Anytime he hits somebody, you feel his presence. But he’s also really smart, really good in coverage, he runs well. He’s the complete package.”

Martinez, outside linebacker Kevin Anderson and cornerback Ronnie Harris are the three holdovers from the 2014 unit that ranked second in the nation in scoring defense (16.4 ppg). In the preseason, there were a lot of moving parts -- youngsters and players who'd made recent position changes -- including starting safeties Kodi Whitfield (receiver) and Dallas Lloyd (quarterback). There was a new defensive end in Brennan Scarlett, who transferred from arch-rival California.

Despite a number of injuries that complicated the jelling process early in the season, particularly up front, things have come together nicely. Whitfield and Lloyd have steadily improved, Scarlett is exceeding expectations playing as a 3-4 end after playing in a 4-3 at Cal, and freshman cornerback Quenton Meeks has become a playmaker in the back half. When Anderson was hurt, sophomore Joey Alfieri stepped in and played well.

“You see those young guys making plays," Martinez said. “Going into fall camp, I didn’t know what to expect. But after fall camp, we knew what we could be.”

Of course, Oregon is a different sort of bird, and the Ducks seem to be peaking offensively after piling up a school record 777 yards -- 477 of those rushing -- against Cal on Saturday.

Said Lance Anderson, "They force you to make plays in space. That was the challenge last year [a 45-16 defeat] and we missed some of those opportunities.”

Those opportunities will be there again Saturday with the Pac-12's North Division again hanging over a Cardinal-Ducks matchup. Stanford's defense appears to have moved past rebuilding, but its truest measure will come against Vernon Adams Jr., Royce Freeman and Oregon's ludicrous-speed offense.