Nearly at the halfway point of college football's regular season, there are 11 Football Bowl Subdivision schools still undefeated. That's down from 16 in 2015 at this time, and it's the second-fewest unbeaten teams through Week 6 over the past seven seasons.

What this means, of course, is anybody's guess. When there were 10 undefeated teams through six weeks in 2014, the College Football Playoff Selection Committee ended up choosing between three one-loss teams (Ohio State, Baylor and TCU) for one spot.

Beware to Alabama, Ohio State, Clemson and Michigan -- the current top four teams in the AP Top 25. In the CFP's first two years, only one top-four team in the AP poll at this stage made the playoff. The future playoff teams were ranked in Week 6 this way by AP voters: 2014 -- No. 1 Florida State, No. 7 Alabama, No. 12 Oregon, No. 15 Ohio State; 2015 -- No. 5 Clemson, No. 7 Michigan State, No. 10 Alabama, No. 19 Oklahoma. (If Louisville fans want a good omen, their team is currently ranked No. 7.)

Going undefeated is incredibly hard. Over the past five years, two FBS teams on average finished the regular season undefeated. Since 2012, undefeated teams came from virtually the same places: the ACC, Big Ten and MAC. (Notre Dame also finished undefeated one year as an independent.)

With that in mind and acknowledging that injuries could happen at any moment, let's rank the remaining undefeated teams by their chances of finishing the regular season without a loss.

1. Clemson (6-0)

Remaining opponents' record: 21-14 (.600)
Toughest game left: at Florida State, Oct. 29

Why they could win them all: The Tigers did it a year ago, so they should understand the grind. The Seminoles will be a challenge on the road, but they often elect not to play the first half. Since Clemson already beat Louisville and avoids Miami and Virginia Tech from the Coastal Division, the rest of the schedule should be fairly easy. Five of Clemson's final six opponents rank 51st or worse in yards per play allowed.

Why they could lose: If Clemson's struggles earlier this season on offense pop up again, that's a red flag against this remaining schedule. The Tigers' running game seems to be back on track. However, they're still 110th nationally in turnovers lost (11) and 100th in red zone offense (78 percent).

2. Boise State (5-0)

Remaining opponents' record: 20-21 (.488)
Toughest game left: at Air Force, Nov. 25

Why they could win them all: The Broncos have wins over the second- and fourth-place teams in the Pac-12 North (Washington State and Oregon State). They have one of the most efficient quarterbacks in the country (Brett Rypien). Their defense gets four sacks per game (tied for second nationally). And they have a major incentive to go undefeated: Houston's loss to a divisional opponent opens the race for Boise State to be the Group of Five team in a New Year's Six bowl. Houston now needs help just to play for its conference championship.

Why they could lose: Boise State lost three Mountain West games in 2015, including at home to Air Force. This year, the Broncos go to Air Force in a game that could determine their division winner. Also looming is Oct. 20 vs. BYU, which beat Boise State last year and has 2016 wins over Arizona and Michigan State plus close losses to Utah, UCLA and West Virginia.

3. Ohio State (5-0)

Remaining opponents' record: 27-10 (.730)
Toughest game left: vs. Michigan (6-0), Nov. 26

Why they could win them all: This is one of the most talented and hungriest teams in the country. So far, Ohio State's youth has been an asset, and the team didn't blink at Oklahoma. The defense is stout and hasn't allowed a rushing touchdown. Unless Michigan State dramatically improves, Ohio State's Nov. 19 game at the Spartans looks much more manageable than it did entering the season. The schedule is set up for the Buckeyes to avoid playing ranked teams in consecutive weeks all year.

Why they could lose: The Buckeyes still face two elite defenses (Wisconsin and Michigan) that could make them one-dimensional. Last week against Indiana, Ohio State ran for 290 yards and threw for 93 as J.T. Barrett missed some deep balls. Barrett has been terrific this season, but if he has an off day against the wrong defense, the Buckeyes could lose.

4. Alabama (6-0)

Remaining opponents' record: 26-8 (.765)
Toughest game left: vs. Texas A&M (6-0), Oct. 22

Why they could win them all: It's Alabama. There's always a chance of going undefeated. Alabama is capable of big plays on offense and defense. The defense has already scored seven touchdowns and the leads the country in rushing defense (2.2 yards per carry, 69.2 yards per game). The offense leads the country in plays of 40 yards or more (17). Quick-strike capability that can swing the momentum of games is a nice luxury for Alabama if it struggles at all moving forward.

Why they could lose: It's Alabama. There's almost always a loss -- even for the best Crimson Tide teams. Alabama's next three games are at Tennessee, vs. Texas A&M and at LSU after a bye. (Alabama's remaining opponents' record is slightly inflated because it plays Chattanooga, which is 6-0 and ranked No. 3 in the FCS poll.) Jalen Hurts has tremendous potential at quarterback. He's also a true freshman taking snaps from a new starting center. Over the past 20 years, only one true freshman quarterback has won a division title in the SEC.

5. Washington (6-0)

Remaining opponents' record: 21-13 (.618)
Toughest game left: at Washington State, Nov. 25

Why they could win them all: The Huskies so far look like a legitimate playoff contender. They have the nation's most efficient passer (Jake Browning), a talented running back averaging almost 100 yards per game (Myles Gaskin) and a stingy defense that gets four sacks per game and only allowing 14.2 points. Chris Petersen has been here before. At Boise State, he finished the regular season undefeated in 2008 and 2009 and almost did the same in 2010 and 2011.

Why they could lose: It's still a small body of work so far given that the Huskies went 7-6 in 2015. They needed overtime this season to win at Arizona, which has a 2-4 record. While there's no clear No. 2 Pac-12 team right now, the closing schedule for Washington has potential potholes: at Utah, at Cal, vs. USC, vs. Arizona State, at Washington State. The Pac-12 hasn't had an undefeated champion since Oregon in 2010.

6. Michigan (6-0)

Remaining opponents' record: 19-12 (.613)
Toughest game left: at Ohio State, Nov. 26

Why they could win them all: The Wolverines' defense is playing at a high level. Michigan leads the country in scoring and total yards. It also ranks second in sacks. Good luck game-planning for Jabrill Peppers on defense, offense and punt returns. Michigan quarterback coach Jedd Fisch is turning another first-year starter, Wilton Speight, into a solid passer. The Michigan State and Iowa trips no longer look as daunting.

Why they could lose: Michigan must go to Columbus, Ohio, to end the season. Even if the Wolverines survive road games at Michigan State and Iowa -- throw out the records when Mark Dantonio faces Michigan -- they would still need to win at Ohio State. The Buckeyes crushed Michigan 42-13 on the road in 2015. Jim Harbaugh has recruited well. Has he recruited that well to win at Ohio State in only his second season?

7. Texas A&M (6-0)

Remaining opponents' record: 18-13 (.581)
Toughest game left: at Alabama, Oct. 22

Why they could win them all: This may be Kevin Sumlin's most complete team. There's actual balance on offense with a rushing attack averaging 274 yards per game (eighth in the country). Defensive coordinator John Chavis' aggressive defense leads the country in forced turnovers. Trevor Knight sometimes is a spotty passer, but he has many receiving weapons and his running ability means he's the type of quarterback who can frustrate Alabama. While at Oklahoma, Knight beat Alabama at the 2014 Sugar Bowl.

Why they could lose: There's the "small" matter of having to beat Alabama on the road, though Texas A&M did this in 2012 and gets a bye before facing the Crimson Tide next week. If the Aggies do defeat Alabama, they have potentially challenging home games against Ole Miss and LSU. Both beat Texas A&M in 2015. The SEC hasn't had an undefeated champion since LSU in 2011.

8. Western Michigan (6-0)

Remaining opponents' record: 18-16 (.529)
Toughest game left: vs. Toledo, Nov. 25

Why they could win them all: Western Michigan plays in the MAC, where six teams in the past eight years went through the league's regular-season schedule undefeated. The remaining schedule of Akron, Eastern Michigan, Ball State, Kent State, Buffalo and Toledo is manageable. Western Michigan's Zach Terrell is one of only six FBS quarterbacks who hasn't thrown an interception in 2016, and he's fourth in completion percentage (70.6 percent). P.J. Fleck, who could be a hot commodity in the coaching market soon, is a remarkable 10 of 11 on fourth-down calls.

Why they could lose: This is new territory for Western Michigan, which is off to its best start since 1941 and had a 1-11 record just three years ago. The program's best season in the past 25 years was 9-3 in 2000. While this has been a terrific start for the Broncos, the reality is they might not be as good as Toledo, which almost won at BYU and is statistically ahead of Western Michigan in yards per play on offense and defense.

9. Baylor (5-0)

Remaining opponents' record: 20-15 (.571)
Toughest game left: at Oklahoma, Nov. 12

Why they could win them all: Have you seen the Big 12 this season? While it's likely the Bears won't go undefeated, there's no game on the schedule right now that looks like a clear loss. Yes, Baylor barely survived at Iowa State. But the Big 12's mediocrity gives Baylor a punchers' chance to run the table. The Big 12's best playoff hope resides in Baylor, which has a lousy nonconference schedule and an uncertain future after its sexual assault scandal.

Why they could lose: Baylor is down to about 70 scholarship players since some players left after Art Briles was fired. Depth figures to be an issue as the season plays out. There's a three-week stretch starting Oct. 29 -- at Texas, vs. TCU, at Oklahoma -- that could make or break Baylor's Big 12 championship hopes. The eye test suggests this team could lose several games before the year ends.

10. Nebraska (5-0)

Remaining opponents' record: 26-10 (.722)
Toughest game left: at Ohio State, Nov. 5

Why they could win them all: If quarterback Tommy Armstrong stays healthy, Nebraska will feel like it at least has a shot in every game. Armstrong averages 7.6 yards per play and is improving as a passer (only two interceptions). He played through cramps to make clutch plays in a game-winning touchdown drive against Oregon. Then again, given how bad the Ducks are, why did Nebraska even need a late drive to beat Oregon at home?

Why they could lose: Look at the schedule, which was front-loaded with four of the first five games at home. (The one road game was against 2-3 Northwestern.) The Cornhuskers play three of their next four on the road, and they're all games they could lose: Indiana, Wisconsin and Ohio State. Facing Ohio State on the road one week after traveling to Wisconsin is not the recipe to stay undefeated.

11. West Virginia (4-0)

Remaining opponents' record: 20-18 (.527)
Toughest game left: vs. Oklahoma, Nov. 19

Why they could win them all: Like Baylor, the Mountaineers could benefit from a very mediocre Big 12. Someone has to win the Big 12. Bizarrely, West Virginia has already had two byes, so there's just four wins to evaluate: Missouri, Youngstown State, BYU and Kansas State. The Mountaineers have needed to win some games by comeback -- a sign either of toughness, mediocrity or both.

Why they could lose: Because of when the byes happened, West Virginia will play its final eight Big 12 games without a week off. The Mountaineers have yet to play a true road game and were fortunate to beat BYU and Kansas State. You have to be the biggest die-hard West Virginia fan to even start contemplating an undefeated season.