Boise State's final ranking in the Bowl Championship Series standings depends more on what other teams do than what the Broncos do. The Broncos, who are fifth in the polls this week, could lose ground even if they win out. Here are three classes of teams that threaten the Broncos:

UNDEFEATED BCS-CONFERENCE TEAMS

Impact: Any undefeated BCS-conference team, except maybe the Big East champion (Cincinnati or South Florida), would finish in front of Boise State.

Teams to watch: The SEC champion (likely Florida, Alabama or LSU), Texas, Iowa, Cincinnati

Key games: Florida at LSU (Oct. 10), LSU at Alabama (Nov. 7), SEC championship game (Dec. 5), Texas vs. Oklahoma (Oct. 17), Michigan at Iowa (Oct. 10), Iowa at Ohio State (Nov. 14), Cincinnati at South Florida (Oct. 15), Cincinnati at Pittsburgh (Dec. 5).

Projection: It would be a surprise if the SEC and Big 12 didn't produce an undefeated or one-loss champion - teams that would finish ahead of Boise State. Iowa doesn't seem like a threat. Cincinnati could be interesting - the Bearcats play in a better league but their schedule isn't appreciably better than the Broncos'.

ONE-LOSS BCS-CONFERENCE TEAMS

Impact: Several one-loss teams from BCS conferences likely would finish in front of Boise State.

Teams to watch: Any SEC or Big 12 team with one loss, USC, Virginia Tech, Ohio State

Key games: Ohio State at Penn State (Nov. 7), Oklahoma State at Oklahoma (Nov. 28), Virginia Tech at Georgia Tech (Oct. 17), USC at California (Saturday), USC at Oregon (Oct. 31)

Projection: The SEC definitely could have a one-loss runner-up, but the other teams that would need to run the table - except maybe Oklahoma in the Big 12 - seem like long shots.

FELLOW BCS BUSTERS

Impact: The BCS is required to take just one qualified non-BCS team. That means if TCU or Houston gets in front of Boise State, the Broncos could get left out with an undefeated record for the second year in a row and the third time in six years.

Teams to watch: TCU, Houston

Key games: TCU at BYU (Oct. 24), Utah at TCU (Nov. 14), Houston at Mississippi State (Oct. 10), Houston at Tulsa (Nov. 7), Boise State at Tulsa (Oct. 14)

Projection: TCU is a problem for the Broncos - the Horned Frogs play in a more-respected league, they have a ranked team on the remaining schedule (BYU) and they beat Boise State in the Poinsettia Bowl last year. Houston probably isn't - the Cougars' schedule, even with three BCS-conference opponents, is weaker than the Broncos' and they don't have a track record of success. Interestingly, Boise State and Houston play at Tulsa - games that could provide a comparison for voters. BYU and Utah, who were in this race when the season began, aren't threats to an undefeated Boise State because Florida State whipped BYU and Utah lost to Oregon, a team Boise State beat.

A little help, please

Oregon has won three straight games since losing the season opener at Boise State. Every time the Ducks win and move up the rankings, the Broncos' resume improves. In fact, if the Ducks can finish 11-1 and win the Pac-10 that might force the Broncos up the BCS standings into the National Championship Game.

Games to watch: at UCLA (Oct. 10), vs. USC (Oct. 31), at Arizona (Nov. 21)

BCS Top 15

Here's a projection of the BCS standings through four weeks compiled by collegebcs.com:

1. Alabama (4-0)

2. Florida (4-0)

3. Texas (4-0)

4. LSU (4-0)

5. Boise State (4-0)

6. Virginia Tech (3-1)

7. TCU (3-0)

8. Cincinnati (4-0)

9. USC (3-1)

10. Iowa (4-0)

11. Ohio State (3-1)

12. Oklahoma (2-1)

13. Houston (3-0)

14. Georgia (3-1)

15. Oregon (3-1)

namey: phoney