Who can beat Alabama?

It’s the question everyone in the college football world has been grappling with for weeks.

The divide between No. 1 and No. 2 looked large enough before Saturday. Then Clemson, Michigan and Washington all lost.

Now it’s back to the drawing board.

With that in mind, we’ve picked the top six candidates that could face Alabama in a playoff and ranked them in order of their ability to challenge the Tide.

Whenever you have a player as dynamic as Louisville quarterback Lamar Jackson, you have a chance. Andy Lyons/Getty Images

1. Louisville: Whenever you have a quarterback of Lamar Jackson's caliber, you have a puncher’s chance. His 46 total touchdowns speak for themselves. His speed and quickness would give Alabama’s front seven fits, and his ability to move the ball downfield through the air would put added stress on a secondary that’s somewhat susceptible to the deep ball. Think of Jackson as Cam Newton and Louisville as the 2010 Auburn Tigers. Newton got the credit, but Michael Dyer was a productive running back, and while that defense wasn’t incredibly talented, it was opportunistic. With Louisville, there’s no looking past Brandon Radcliff, who is averaging 7.2 yards per carry, and there’s no discounting a defense that ranks in the top 25 in sacks and has forced 22 turnovers, which is four more than Alabama.

2. Clemson: Let’s not forget what Deshaun Watson did to Alabama’s defense last year. We’re talking about 478 total yards of offense and four touchdowns. If not for a couple of special-teams plays, Clemson wins the national championship. So even if he hasn’t been himself this season, he has that capability in him. It doesn’t hurt that he has Wayne Gallman at running back and Mike Williams at receiver, either. But what really gives Clemson a good shot at beating Alabama is its front seven. Led by Christian Wilkins, that group is ferocious and has the fifth-most sacks in the FBS. And if LSU showed us anything, it’s that if you pressure Jalen Hurts, you can rattle the freshman QB.

3. Ohio State: Yes, these Buckeyes are young. Yes, you don’t know what you’re going to get from them from week to week. But we’re talking about just one game, and if everything comes together there’s no doubt they’re one of the best teams in the country. In terms of talent, Ohio State might be the one program that most closely resembles Alabama. At quarterback, they’re all set with J.T. Barrett, who has both talent and experience and is as adept at running the football as he is passing it. His defense may be inconsistent, but it presents a unique challenge for Alabama. Where the Tide rank 68th in red zone touchdown percentage on offense, the Buckeye defense ranks second in keeping teams from scoring touchdowns in the red zone

4. Oklahoma: Forget those early-season losses to Houston and Ohio State. Since then, Oklahoma has become a different team, reeling off seven straight wins. The Sooners will need some help to reach the playoff, of course, but they may be the one team that no one wants to see sneak in. Why? Go look at that offense. Baker Mayfield is working his way back into the Heisman Trophy conversation with 33 touchdowns and just seven interceptions. He’s not being overly deferential when he says that receiver Dede Westbrook deserves a trip to New York more than he does. Westbrook, with 14 touchdowns and 1,284 yards, has become arguably the best receiver in the country. Coupled with a terrific tandem of Joe Mixon and Samaje Perine at tailback, Oklahoma has an offense that would force Alabama to defend all parts of the field. The question on the flip side is whether the Sooners could play enough defense to stop the Tide from running the up the score.

5. Michigan: Even with Wilton Speight sidelined, there’s a lot to like about this Michigan team, starting with Jim Harbaugh. You can say what you want about Harbaugh’s antics as long as you acknowledge that the man knows how to coach. Give him a month to prepare for Alabama, and he’ll come up with something. With Jake Butt, De'Veon Smith or Amara Darboh, there’s a nice nucleus to work with on offense. The problem is Michigan runs a pro-style system that would play into Nick Saban's hands. Just ask Michigan State how that worked out. But really it’s the Wolverines' defense that makes you think they could make a game of it, possibly turning it into a low-scoring slugfest, a la LSU. Michigan currently ranks No. 1 in the FBS in points and yards per game allowed, and more importantly it knows how to get to the quarterback, posting the sixth-most sacks in the Power 5. That pass rush, combined with the ability to use star linebacker/defensive back Jabrill Peppers as a QB spy, would put Hurts under enormous pressure.

6. Washington: You can’t make a mistake against Alabama and expect to win. In Jake Browning, Washington has perhaps the most efficient quarterback in the country. Even after a subpar performance against USC, the sophomore has an incredible touchdown-to-interception ratio of 7:1. It’s not just him. The Huskies go three-deep at receiver with John Ross (896 yards), Dante Pettis (596 yards) and Chico McClatcher (401 yards), and in Myles Gaskin they also have a 1,000-yard rusher. With the second most turnovers forced in the FBS (24), the defense isn’t half-bad either.