The Trail Blazers walked off the floor of the AT&T Center in San Antonio following a 104-82 drubbing in Game 5 of the Western Conference Semifinals last May, knowing they were no match for the soon-to-be NBA champion Spurs.

The Spurs had just completed the "gentleman's sweep" of the Blazers, thoroughly dominating Portland in four wins. The Blazers had somehow avoided a clean sweep with a Game 4 win that seemed more like a courtesy chuckle at Portland's ill-timed joke.

The message was clear: To take the next step in a quest for their first title in 38 years the Blazers needed to make some changes. And it started with defense.

"We got our ass kicked against San Antonio," Blazers coach Terry Stotts said. "If we want to get better, the way we're going to get better is defensively. That was the commitment everybody made."

The re-shaping of Portland's defensive identity had started in 2013. But the beating at the hands of the Spurs crystallized in the minds of the Blazers exactly what the commitment would entail.

Transformation through imitation

With 2014 NBA Finals MVP Kawhi Leonard looking on, Spurs coach Gregg Popovich calls a play. Terry Stotts used Popovich's defense as a model for the Blazers.

If imitation is the sincerest form of flattery, Frank Vogel, Tom Thibodeau and Greg Popovich have reason to blush.

Heading into his second season as the Blazers head coach in 2013-14, Stotts used the blueprints laid by Vogel's Pacers, Thibodeau's Bulls and Popovich's Spurs as the guide for Portland's defensive transformation.

"We looked at Indiana and Chicago and San Antonio and they were very conservative in their approach," Stotts said. "They protected the paint, they dropped on pick and rolls, they took away angles to the basket. That was the process going into last year."

In Stotts' first season in Portland the Blazers lacked a true center. JJ Hickson started 80 games at center and the big man options behind him were two rookies, Joel Freeland and 20-year-old Meyers Leonard.

With a roster filled with athletes and no true rim protecting big man, Stotts had the Blazers "show hard" on pick and rolls. Their goal was to slow the ball handler before scrambling back to recover to the man rolling into the paint. The idea was that the aggressiveness on the perimeter would keep teams from getting to the rim where the Blazers didn't have a shot altering presence.

It didn't work very well. Portland was terrible defensively in 2012-13, ranking 26th in the league in efficiency and conceding 109.2 points per 100 possessions.

At the conclusion of the season, using the league's best defenses as a roadmap, Stotts and his staff decided to make wholesale changes.

"We came in saying, 'Look we were bad defensively; it starts with pick and rolls. We need to change what we do,'" Stotts said.

The team didn't wait for training camp in the fall to start implementing changes. During summer league practices in July, the Blazers were already installing new defensive principles.

"I remember after my rookie year they had the summer league camp at the (practice facility) and I was there and I went to a few practices and we started putting it in during summer league," Blazers point guard Damian Lillard said.

The Blazers were loaded with offensive firepower, but Stotts had to convince his team that they needed to make a commitment to the other side of the floor.

"(Stotts) said 'We've got to be a better defensive team if we're going to be what we're capable of being,'" Lillard recalled. "From that point on everybody just took pride in it."

Instead of showing hard on pick rolls, the Blazers would now "blue" screens, using the screener's defender (typically a big man) to clog the middle of the floor and push the ball handler to the sideline. Sometimes the screeners would change the angle of the pick, in which case the Blazers maintain their principles, chasing the ball handler over the pick towards the waiting big man.

"You've got to force them in a direction," Lillard said. "You've got to make them go away from the screen and we've done a good job of that. It comes natural. When we push them away from the screen we've got to be trusting in the fact that our big man is going to drop low and be able to cover for us."

Stotts said the fundamental shift in defensive philosophy was going to happen even if the team didn't acquire an impact big man. But on the night of the 2013 NBA Draft the Blazers acquired the "missing-link" in their defensive transformation.

Man in the middle

Robin Lopez (42) blocks the shot of San Antonio Spurs center Jeff Ayres (11) in a game at the Moda Center in February 2014. Lopez's ability to protect the rim has helped transform the Blazers into an elite NBA defense. Photo by Bruce Ely / The Oregonian

"RoLo changed everything," Nicolas Batum told The Oregonian/OregonLive last spring.

More accurately, everything was already changing and Robin Lopez made it work.

Neil Olshey traded the rights to rookie big man Jeff Withey, cash and two future second round picks in order to acquire Lopez from the then-New Orleans Hornets. The deal was largely unheralded at the time, but now looks like one of the best bargains of the last two years.

"The addition of Robin Lopez was key to their defense," Pistons coach Stan Van Gundy said. "It let LaMarcus (Aldridge) not have to play centers all the time. It gave them a guy that was more comfortable being a basket protector and sealing off the lane."

Most importantly, Lopez gave the Blazers a defensive-minded big that fit perfectly with their new defensive scheme. Lopez is a savvy position defender, but he isn't lightning quick. In New Orleans, he was asked to show on pick and rolls, chasing ball handers 25-feet from the rim before scrambling back to recover. The scheme didn't fit his skill set, but in Portland the Blazers were installing a defense that would highlight Lopez's defensive prowess.

"We wanted to get him because he fit what we needed on a lot of levels," Stotts said of Lopez. "Defensively, having a legitimate center -- we had JJ Hickson at center the previous year -- we knew we wanted a true center. We really didn't look at what happened in New Orleans other than watching him, but we knew what he could bring."

With Lopez in the middle, the Blazers were set to make major defensive strides. But the improvement didn't happen overnight. The Blazers had spent half the season settling into Stotts' new scheme, and by the time the stretch run arrived it all started to click. From February 1, 2014 through the end of the regular season, the Blazers ranked in the Top 10 in defensive efficiency.

"It wasn't a seamless transition," Stotts said. "We came out of the gates with our offense, and our defense was slow to catch up. The second half of the season it got better and better. "

Once the Blazers truly understood how they wanted to defend teams -- 40 games into the season -- they started to see results.

"Just getting comfortable with it ... and then we got pretty good at it," Lillard said. "We saw that it was working in our favor so we started to do it a little harder. We started to understand it better and we got better as a team."

The depth of defensive improvement manifested itself in the series victory over the Houston Rockets in the first round of the 2014 Western Conference playoffs. The Blazers disrupted Houston guard James Harden all series, limiting him to 29 percent three-point shooting and allowing him to crack 50 percent from the floor in just one game.

"I think the Rockets series is the best example," Lillard said. "We really defended and we competed and we played at a high level."

"That was kind of our mindset. We realized how good we could be."

Smart not sexy

Blazers coach Terry Stotts gathers the team during a timeout as the Portland Trail Blazers face the San Antonio Spurs at the Moda Center on February 25, 2015. With a revamped defense leading the way, Stotts has the Blazers poised for another playoff run. Photo by Bruce Ely / Staff

The Blazers have been a Top 10 defense all season, spending most of the year entrenched in the Top 5 in the NBA in defensive efficiency.

"We've picked up where we were last year," Stotts said. "We've shored up our transition defense, we've shored up our attempts at the rim which was our biggest thing. By really emphasizing our transition defense and not letting the ball get to the rim as much it improved the other aspects."

The only true change from a season ago defensively is the Blazers commitment to getting back in transition. Players in the corner don't crash the offensive glass; instead they sprint back in transition. The Blazers are content to let Lopez, an excellent offensive rebounder, contest for offensive rebounds while the other four players get back and set the defense.

What the Blazers have built is one of the smartest defenses in the league. Witness:

As of Monday, they forced the

They rank

They force the second-most attempts in the non-restricted paint area.

Forty-seven percent of their opponents' shots come from the mid-range and in the lane away from the rim, the lowest percentage shots in the league.

As more and more NBA offenses center around three-pointers, the Blazers are the best in the NBA at limiting long range shots. Portland concedes the fewest three-point attempts and has the second-lowest opponent three-point percentage.

"We want to force midrange shots," Lillard said. "It's the lowest percentage shot in the league. Guys like getting to the rim and guys like shooting threes. That's just what the league is now. We like to force people to shoot that (midrange) shot."

The Blazers also put an emphasis on limiting corner three-point attempts, allowing the fourth-fewest corner threes in the league.

"The corner is the closest three-point shot. When someone gets a look like that it's all bets off," Lillard said. "You get them off the line and then we'll figure it out from there. Guys got to step up and help out, but we don't want to give up threes."

In year two of the new defense, Stotts is more willing to let the Blazers help and switch on defense as necessary. Last season, he was stricter about bluffing help and staying out of defensive rotations. The Blazers returned 13 players from last season and the trust from player to player -- and down from the coaching staff -- translated to defensive success.

The Blazers rank in the Top 10 in the NBA in defensive efficiency.

"Last year I think, more so, it was new to us so we wanted to keep it that way," Lillard said about having more freedom to rotate and scramble on defense. "Keep it simple, do it how they brought it up to us in training camp and not try to mess with it."

Stotts says he constantly gets asked about the Blazers defensive improvement, but he doesn't think people are parsing through film to conclude Portland is an elite defensive group.

"If we didn't have all the Internet analytics I don't think necessarily people would look at our team and say they're a great defensive team," Stotts said.

He's probably right. The Blazers don't have a traditionally sexy defense. They don't force tons of turnovers; they aren't the swarming, trapping defense that made the Miami Heat so appealing during their four consecutive NBA championship appearances. Portland's ascent into the realm of great NBA defenses is about forcing teams to take the most difficult shots.

Stotts is quick to point out that the Blazers are a strong defensive team even by more traditional measures. One example: Portland is fifth in the league in opponent field goal percentage.

Stotts says advanced stats have been a major part of the Blazers defensive transformation, and he incorporates analytics into much of his coaching. It isn't uncommon to see quarter-by-quarter defensive rating written on the white board in the Blazers locker room following a game. But the Blazers coach isn't spending practice time telling his players about defensive win-shares.

"I don't inundate them with numbers. I'm selective with what we show them," Stotts said. "Whether it's points per possession or our defensive rating. They are aware of the numbers. They know that we have the numbers to back up the things that we say."

More so than any analytics, Lillard credits continuity and familiarity with the Blazers defensive improvement.

"This year it's just a mix of us doing it longer, us being comfortable with each other, us communicating with each other," he said. "That's just being committed to being a better defensive team."

-- Mike Richman

mrichman@oregonian.com | 503-221-8162 | @mikegrich