FOUR DOWNS

1. CORNERSTONES

If this is going to be another dominant Boise State defense, that success almost certainly will start with senior cornerbacks Jamar Taylor and Jerrell Gavins. The pair can take away the deep ball, collect interceptions and give coordinator Pete Kwiatkowski the freedom to blitz. “We plan on being the best, and that’s what we’re going to be — the best in the Mountain West, the best in college football,” Gavins said.

2. CHANGES ABOUND

The Broncos lost the entire front seven and both starting safeties. They also lost half of their defensive coaching staff — Marcel Yates (defensive backs, Texas A&M) and Jeff Choate (nickels, Washington State), who were original members of Chris Petersen’s staff. The starting lineup could include as many as five freshmen and sophomores.

3. END GAME

The least experienced position is defensive end, where three of the top four players will make their major college football debuts this season. But this should be a fun group to watch because of the energy and athleticism of players like Demarcus Lawrence, Sam Ukwuachu and Beau Martin.

4. LAST LINE OF DEFENSE

For the first time since 2005, Boise State doesn’t possess a veteran safety. Sophomores Lee Hightower and Jeremy Ioane are expected to start — and there’s even less experience behind them. Senior Hazen Moss, the only upperclassmen in the group, has spent his career as a reserve and special-teamer.

TO-DO LIST

STOP THE RUN: Senior linebackers Tommy Smith and J.C. Percy and veteran tackles Mike Atkinson and Ricky Tjong-A-Tjoe give the run defense plenty of backbone.

FORCE 30 TURNOVERS: The Broncos have collected at least 30 takeaways in four of the past eight years — all of their perfect regular seasons.

DEVELOP DEPTH: The Broncos have few experienced backups. The freshman classes — true and redshirt — will need to plug holes.