With twists, of course, as the face of the opponent changes.

And then there is the weekly shuffling that he must do as he checks who is available and who is not.

Boston College has a bye this week before resuming its season next week at Virginia. But defensive coordinator Billy McGovern does not; his cycle of preparation continues.

McGovern, in his first year as defensive coordinator after being linebackers coach at BC for nine years, has been forced to mix and match personnel from the get-go.

At the start of the year, he had to adjust to switches in the line as Ron Brace and B.J. Raji moved on to the National Football League.

He had to adjust to a new look at linebacker, as Mark Herzlich (cancer) and Mike McLaughlin (Achilles’ tendon) were missing from the lineup, a fact of life that sped up the insertion of true freshman Luke Kuechly into the mix. He had to factor in a new starter at strong safety as Marcellus Bowman replaced veteran Paul Anderson.

And, for the most part, it has worked. The Eagles have had only one real defensive meltdown - a 48-14 loss at Virginia Tech Oct. 10 - in a season in which the defense has had to carry the burden while the offense searched for an identity.

With a 6-3 record - bowl-eligible for the 11th straight season - BC has surprised some people.

McGovern says there is no secret formula.

“We try to figure out what we can do and the best way to do it,’’ said McGovern, who also is one of BC’s best recruiters and has established a talent pipeline to Boston from New Jersey, where he grew up. “It’s not brain surgery.’’

McGovern says his basic defensive philosophy comes from his longtime friend and now boss, head coach Frank Spaziani, whom McGovern replaced as defensive coordinator.

“Spaz makes it simple,’’ said McGovern with a laugh. “He is always telling the players, ‘If you think, you stink.’ ’’

That philosophy of following your instincts - just play and react rather than analyze - has worked well for the Eagles in McGovern’s tenure.

“That’s old stuff,’’ said Spaziani with a laugh. “Goes back to my days in the CFL. I actually got it from an old high school coach in New Jersey.’’

“Again, we’re not reinventing the wheel here,’’ said McGovern. “We try and prepare our kids and show them [opponents’] tendencies on offense and simply tell them to go out and make a play.’’

No one has done a better job of that than Kuechly, who has had a phenomenal freshman season, leading the team in tackles and absorbing the defensive system quicker than anyone imagined.

“Coach Spaz told me that at the beginning of the season,’’ said Kuechly. “He said, ‘Luke, quit thinking. If you think about it, you are going to second-guess yourself.’ He said, ‘Just go play.’ ’’

In last week’s 31-10 win over Central Michigan, Kuechly again was a star, intercepting a pass and returning it for a touchdown for the first time in his career - college or high school.

What was significant was that it was a play Kuechly had seen during the week in practice. McGovern and the defensive staff had studied enough tape of Central Michigan to recognize what plays the Chippewas would run in certain situations and formations.

Kuechly didn’t think as much as he reacted, especially after safety Wes Davis saw the same thing and told Kuechly what to expect.

McGovern, who was a star at Bergen Catholic High School in New Jersey (he was on the All-Century Bergen County team) and a consensus All-America defensive back at Holy Cross, is showing the same tendencies as a coach.

“It’s just working on the fundamentals and working on eliminating mistakes,’’ he said. “The kids are getting better as they get more experience and are learning something each day of the week.’’

And they are reacting rather than analyzing. They are playing rather than thinking, and they definitely do not stink.