The College Football Playoff field is set. It may have been a controversial year with Ohio State and Notre Dame getting in over the likes of Texas A&M or undefeated Cincinnati, but these four teams competing for the national championship have some spectacular players. And in the end, the playoff is all about matchups. 

With the semifinals kicking off on New Year's Day, let's get to know the impact players on all four teams as we rank them all the way to the most important in the field. We're looking at offense and defense, with a mix of big names and some that you need to know. 

Keep in mind that these rankings don't necessarily reflect which players are better than others. There is some crossover, to be sure, but this is about their impact on the game. Obviously, some deserving names are going to be excluded, but that's the bittersweet outcome of having so many talented players in the College Football Playoff field. 

Let's get to it. 

20. Clemson WR E.J. Williams

There's a strong case for Amari Rodgers or Cornell Powell on this list, but in terms of breaking open and changing the game, Williams has a chance to be a Justyn Ross-type. Clemson's coaches don't shy away from giving freaky freshmen a chance to shine on big stages. Williams only has 19 grabs and two touchdowns, but he's come on late in the year. 

19. Notre Dame TE Michael Mayer

Notre Dame's tight ends need to play a pivotal role against Alabama if the Irish are going to pull the upset. One of his best performances of the season came in the regular season win over Clemson in which he caught five passes for 67 yards. As a freshman, Mayer is a bit unsung as an impact player, but he's a star-in-the-making and can show some flashes on the biggest stage. 

18. Ohio State DL Tommy Togiai

We'll get into another one of Ohio State's defensive linemen below, but this is going to be a big matchup in the Sugar Bowl. How will the Buckeyes' defensive line, which is really anchored by its defensive tackles, perform going up against a weaker Clemson offensive line? Togiai was a second-team All-Big Ten selection this year and had three sacks earlier in the season against Penn State

17. Clemson DB Nolan Turner

A targeting penalty from the ACC Championship Game will sideline Turner for the first half of the Sugar Bowl. In its own way, that might prove just how valuable Turner is if the Buckeyes have early success in the passing game. In any case, Turner is a defensive leader with 52 tackles who has played nearly 500 snaps this season. 

16. Ohio State CB Shaun Wade

The Buckeyes churn out first-round cornerbacks on a yearly basis, and Wade could be the next one. While Wade has had a few ups and downs this year -- he leads the team with two picks but was beaten multiple times against Indiana -- there's no denying his lockdown potential. Not to mention Wade has a bit of redemption on his side after being ejected in the semifinal loss to Clemson last year. 

15. Notre Dame RB Kyren Williams

Ian Book may have elevated his game this year, but Notre Dame's bread and butter is still its ground attack. As a first-year starter, Williams has taken on the bell cow duties with 1,061 yards and 12 touchdowns. But he's been more than just a guy toting the rock. Williams has been lauded for doing the dirty work in pass protection, too. 

14. Notre Dame QB Ian Book

In a playoff field of quarterback superstars, Book doesn't have the same ceiling as Jones, Fields or Lawrence. But, man ... if he didn't play lights-out football for about six weeks from late October to early December. He's made a lot of throws that we didn't see out of him in his first couple of years while cutting down on mistakes. He's also been an effective runner with eight scores on the ground. 

13. Clemson RB Travis Etienne

The senior is the ACC's all-time leading rusher and he can hit three 1,000-yard seasons with a good playoff run. He hasn't had the offensive line help like in year's past, and that's affected his numbers a lot. He's only hit the 100-yard rushing mark three times in 2020. but he's still an option out of the backfield in the passing game with 44 catches on the year. 

12. Ohio State DL Haskell Garrett

The Buckeyes defensive line is anchored by Garrett, who, according to Pro Football Focus, was the highest-graded defensive lineman in college football this season. Garrett doesn't have the most glamorous job on the defensive side, but he's disruptive while also commanding a lot of attention in the interior. Going up against Clemson's offensive line, Garrett could have a huge impact. 

11. Clemson LB James Skalski

Notre Dame's midseason victory over Clemson had less to do with the Tigers missing Trevor Lawrence and more to do with defensive absences, including Skalski, who missed three games this year due to a groin injury. His return has made an obvious difference as Skalski is the heart and soul of the Tigers' defense. His leadership and competitiveness is only matched by his production (he was second on the team in tackles a year ago). 

10. Notre Dame DB Kyle Hamilton

The Fighting Irish's defensive backs are going to be paired against some of college football's best pass-catchers in the Rose Bowl. Hamilton leads Notre Dame in tackles, but as the team's safety, he's going to be responsible for pass breakups and being the last line of defense against guys like Devonta Smith and John Metchie III

9. Alabama CB Patrick Surtain II

One of Alabama's first-team All Americans, Surtain was also PFF's highest-graded corner for 2020. He's a shutdown player who's taken on some of the best pass-catchers in college football. There are some big bodies in Notre Dame's passing offense, but Surtain has the length and size (6-foot-2, 202 pounds) to play physical defense against those bodies. 

8. Notre Dame LB Jeremiah Owusu-Koramoah

The All-American is tied for the team lead with 56 tackles. JOK is everywhere. He's been forcing fumbles -- he has three on the season -- and getting into the backfield (11 TFLs). Notre Dame's defense is going to have its work cut out for it against Alabama, but Owusu-Koramoah is as disruptive as any linebacker in the nation. Defensive success against the Crimson Tide starts with him. 

7. Alabama OL Alex Leatherwood

Center Landon Dickerson is the unsung hero of the offense, but he's out after suffering a knee injury in the SEC Championship Game. Leatherwood is another one of Alabama's top offensive linemen, and at tackle he's instrumental in Mac Jones' protection. Against the likes of Daelin Hayes and/or Adetokunbo Ogundeji from Notre Dame, Leatherwood is going to have a huge matchup in the trenches. 

6. Ohio State WR Chris Olave

Fields is viewed as the overall better player in terms of his draft stock, but I'd argue Olave has already proven he's just as valuable for Ohio State's offense. Olave, along with more than 20 other teammates, was absent for the Buckeyes' Big Ten Championship Game against Northwestern. As it so happened, Fields had his worst day throwing the ball with a 44% completion rate and two picks. Part of that is Northwestern's good pass defense, but not having Olave clearly had an impact. With the Big Ten adjusting its COVID-19 protocols from 21 days to 17 for positive tests, Olave should be available for the Sugar Bowl. 

5. Alabama QB Mac Jones

Hey, remember when Bryce Young was going to lead Alabama's offense in 2020? Good times. That's not a knock on Young, but rather a testament to how Jones embraced the competition and has been exceptional in leading college football's most frightening offense. Yes, he has a great offensive line and elite weapons around him, but Jones has made some NFL throws, too. He's on track to pass Tua Tagovailoa's passing mark from 2018, and should be the program's first 4,000-yard passer in a single season.

4. Ohio State QB Justin Fields

He's had a couple of sub-par games, but when he's on, Fields is as dangerous as any quarterback in the country. Some of his struggles can be attributed to coach Ryan Day getting too pass-happy in his play-calling. Some of it is Fields trying to do too much. But let's not overthink this: Fields is a bonafide stud. His downfield ball will test Clemson's defense, and obviously the Tigers will have to account for him as a runner. 

3. Alabama RB Najee Harris

It was going to be hard for Alabama to have three Heisman finalists. Unfortunately for Harris, he was the odd man out, though he did finish fifth in the voting. Still, Harris is having an All-American season, leading the FBS with 24 rushing touchdowns and sitting third with 1,262 yards at 5.9 yards per attempt. His blend of size, speed, lateral movement, burst, toughness and receiving ability has made him the overall best player at the position. His versatility in Alabama's offense is invaluable. 

2. Clemson QB Trevor Lawrence

For anyone who needed it, Lawrence's 412 yards of total offense and three touchdowns in the ACC Championship Game blowout over Notre Dame was a reminder that he's still college football's best quarterback. His 329 yards per game ranks seventh nationally in that category. I don't know that it's enough to win the Heisman, but he's put together another monster season -- and without great offensive line play. If Clemson is going to win a national title, it's going to be on Lawrence's shoulders. 

1. Alabama WR Devonta Smith

The Heisman chants have grown louder, and there's a real possibility Smith is the first true wide receiver to win the award since Desmond Howard in 1991. He leads the nation in receptions (98) and yards (1,511), and is second with 17 touchdowns. He's taken on so more responsibility in the passing attack after Jaylen Waddle's injury, and his impact has already been tops on a team full of other Heisman contenders and future NFL draft picks. He's the best player on what is probably the best team.