On Aug. 31, 2013, on a clear night in Missoula, Mont., the first play of the first game of the first season of Nate Woody’s tenure as Appalachian State defensive coordinator was a sack of Montana’s quarterback. On the second play, the Mountaineers stopped the Grizzlies for no gain.

Installed that spring after he was hired from Wofford, Woody’s defense was off and running. However, many of the remaining 833 snaps that season were not quite as convincing, part of a grim season for first-year coach Scott Satterfield, Woody and the entire team.

“I think that the 2013 season was a season we’ll all remember and wish we could forget about,” said Appalachian State defensive coordinator Bryan Brown, who that year was in his second season as the team’s cornerbacks coach. “But it was our growing pains, especially the 2013 season and the first half of the 2014 season.”

Georgia Tech fans seeking evidence that the Yellow Jackets defense can be transformed into a world-beating unit  in Woody’s first season as its coordinator won’t find it in his first autumn in Boone, N.C. By a variety of statistical measures – points, yards, yards per play and opponent passer rating among them – the Mountaineers held fairly steady from 2012 to 2013. It is undeniable, though, that there were factors that they were dealing with that Tech is not.

“That was probably our most down year so far, and after that, we took off,” said Ronald Blair, then a Mountaineers defensive end and now a San Francisco 49er.

The 2013 Mountaineers finished the season 4-8, their first losing season since 1993, ending a run of eight consecutive FCS playoff appearances, the first three of which yielded national championships. For Woody, the challenges were everywhere. He had been hired by Satterfield, but was the only addition to the defensive staff.

“That first year, he had his hands on everything,” Brown told the AJC. “And it was because he was the only one who knew his defense. But he taught it to us and was patient with us, but it was a lot of growing pains.”

The same held for the players.

“It was just getting a feel for it,” Blair said. “Like when you first do something, it all looks good on paper, but you don’t really get a good feeling until you do the reps over and over again against teams and you figure how they try to scheme you, who they’re trying to block. That first year, we were trying to figure out how people were going to attack us. Once we figured it out, it was to the sky from there.”

Finding players that fit the scheme was another challenge. Appalachian State was particularly thin at linebacker, as the Mountaineers were shifting from a 4-2-5 (four linemen, two linebackers, five defensive backs) to Woody’s 3-4 (three linemen, four linebackers). One of his starting outside linebackers had played the previous season at running back. Another outside linebacker came from safety.

In one game week, Woody made a scout-team offensive lineman his starting nose tackle, a position of great importance in his defense.

“You’ve just got some guys out there in space, a couple outside linebackers, that really weren’t those type of players,” Brown said.

Further, Appalachian State had just commenced its transition from FCS to FBS. As a result, the Mountaineers were not eligible for the Southern Conference title nor postseason play. Mix that in with a new head coach replacing one who had been highly successful (Jerry Moore), and three losses in the first five games by a field goal. Morale was not high.

“That whole year was really, really tough,” Brown said.

Appalachian State ended the season giving up 28 points a game, 1.3 points below the 2012 average. The yards-per-play average was 5.8, a tick better than the 2012 rate of 6.1. Opponent third-down conversion rate and completion percentage were worse. Brown did see improvement over the course of the season.

“Oh, yeah,” he said. “Throughout the whole season, you could sense it and feel it – guys were starting to get the hang of it.”

The tide began to shift next season. The Mountaineers started 1-5, and opponents averaged 427 yards per game. Over the final six games, the number dropped to 268, and Appalachian State won all six while leading the Sun Belt in total defense.

Woody and the Mountaineers lifted off for good in 2015. Players he recruited for his defense were taking the field. The depth that he worked so hard to develop was paying dividends. After coming to Appalachian State with a scheme that Brown described as “bend but don’t break,” his adaption to a more aggressive style in collaboration with his staff took shape.

In 2015, despite the fact that much of the roster had been recruited while Appalachian State was still in FCS, Appalachian State led the Sun Belt in scoring defense (19. 1 points per game), total defense (314.5 yards per game) and sacks (2.8 per game).

“Everyone knew what calls to make. Everyone was flying around with confidence,” said Blair, who was conference defensive player of the year in 2015. “That first year was kind of testing the water.”

After spring practice, preseason and one game with Woody, coach Paul Johnson has been encouraged, but acknowledged in the preseason that “Rome wasn’t built in a day. They’re not going to come out right from the start and look like the Steel Curtain,” referencing the famed Steelers defense of the 1970s.

The 2018 Jackets, who play South Florida on Saturday in the second game of the season, are different from the 2013 Mountaineers for multiple reasons. One, Woody stepped into a far more stable situation. Also, while Tech also ran a 4-2-5 with former coordinator Ted Roof, the players he inherited appear to be better fits for his scheme than his original defense at Appalachian State. He has two assistants, safeties coach Shiel Wood and defensive line coach Jerome Riase, who came from Wofford, where the scheme was similar. And Woody has more experience in teaching his defense for the first time. (Woody, per team policy, is not available to speak with media.)

Still, growing pains undoubtedly are to come. How quickly they yield growth spurts remains to be seen.