Tua Tagovailoa and Trevor Lawrence battled each other for the national championship this past January and may well have a rematch, but they won't need to compete for the honor of first player selected in the NFL draft. Assuming both players declare when first eligible, Tagovailoa could go No. 1 in 2020, with Lawrence following suit in 2021.

There's a lot of football to be played between now and then, though, and there are a bunch of players talented enough to get drafted before those two stars.

Based on how NFL teams have been drafting lately, quarterbacks are the primary candidates for the top spot. Sixteen of the past 22 No. 1 overall picks have been quarterbacks, so it should come as no surprise that gunslingers make up more than 50 percent of our list.

Defensive linemen and offensive tackles have also been No. 1 picks in the recent past, though, so we made sure to include two of each.

Players are listed in alphabetical order by last name, regardless of whether they'll be eligible in 2020 or 2021.

For more college football and NFL draft talk, check out the Stick to Football podcast with B/R's lead draft expert Matt Miller.

Honorable Mentions

Grant Delpit, S, LSU (Eligible 2020)
Tyson Campbell, CB, Georgia (Eligible 2021)
Patrick Surtain, CB, Alabama (Eligible 2021)

All three of these SEC defensive backs possess the potential to immediately become stars in the NFL, a la Derwin James, Jalen Ramsey or Jamal Adams. Any franchise with even the slightest concerns in its secondary would be wise to snatch up one of these guys with a top-10 pick.

However, using a No. 1 overall pick on a defensive back would be almost unprecedented. The last time it happened was when the Pittsburgh Steelers took Gary Glick in 1956.

Jerry Jeudy, WR, Alabama (Eligible 2020)
Najee Harris, RB, Alabama (Eligible 2020)
Justyn Ross, WR, Clemson (Eligible 2021)
Tee Higgins, WR, Clemson (Eligible 2020)

These four skill-position players are going to get plenty of time in the spotlight, as Alabama and Clemson figure to square off in the College Football Playoff for the millionth fifth consecutive year. One could also argue for Clemson RB Travis Etienne to be included on this list, although the internet community of 2020 way-too-early mock drafters seems to have collectively forgotten how magnificent he was this past season.

Same as the defensive backs, though, recent history is not on their side here. Neither a running back nor a wide receiver has gone No. 1 overall since Keyshawn Johnson in 1996. It has been 23 consecutive years of either quarterbacks (16), defensive ends (four) or offensive tackles (three). But if Jeudy has another campaign anything like he did in 2018, he'll be in the conversation for a top-three pick.

Yetur Gross-Matos, DE, Penn State (Eligible 2020)
Micah Parsons, LB, Penn State (Eligible 2021)

Oklahoma just went back-to-back with the No. 1 picks, so could Penn State be the next team to pull it off? Gross-Matos recorded 20 tackles for loss in 2018 and is likely to be either a second-team or third-team preseason All-American. Meanwhile, Parsons led the Nittany Lions in tackles as a true freshman and should have a lot of allure among NFL scouts as a guy who could thrive at either linebacker or defensive end.

Xavier Thomas, DE, Clemson (Eligible 2021)

Despite suiting up behind Clelin Ferrell and Austin Bryant on Clemson's depth chart, Thomas—the No. 3 overall recruit in the 2018 class, according to the 247Sports composite rankings—made a significant impact as a true freshman. He's the early top candidate for first non-quarterback selected in the 2021 draft, but he'll need to have two phenomenal seasons to leapfrog all those QB options.

Brock Purdy, QB, Iowa State (Eligible 2021)

Purdy averaged 10.2 yards per attempt and had a 169.9 passer efficiency rating last year, leaving all other true freshmen, including Trevor Lawrence, in the dust. An encore season anything close to that would put him in the hunt for the No. 1 pick in 2021, even though he's only 6'1" and even though Iowa State has only produced one first-round pick in program history—George Amundson, No. 14 overall in 1973.

Jacob Eason, QB, Washington (Eligible 2020)

After his freshman season at Georgia in 2016, Eason was an extremely early candidate for the No. 1 pick in the 2019 draft. But a 2017 season lost to injury and a 2018 season lost to transfer rules have caused everyone to forget about this guy. A hot start in his new threads against Eastern Washington, California and Hawaii would put him back on the NFL's radar in a hurry.

Sam Ehlinger, QB, Texas (Eligible 2020)

Good luck finding anyone who currently has Ehlinger projected as a first-round pick, but he's bound to drum up a lot of draft hype if he has another season with more than 40 total touchdowns while leading Texas to the College Football Playoff.

A.J. Epenesa, DE, Iowa

Eligible to Be Drafted: 2020

2018 Stats: 37 tackles, 16.5 tackles for loss, 10.5 sacks, four forced fumbles, four passes defended

Reason to Buy

There is not a single returning player who had more sacks in 2018 than Iowa edge-rusher A.J. Epenesa. The true sophomore—who was a consensus 5-star recruit in the 2017 class—had at least one sack in nine of 13 games. And he finished strong with 6.5 tackles for loss, 3.5 sacks, two forced fumbles, two passes defended and a fumble recovered for a touchdown in his final three games.

Here's the ridiculous part: Epenesa has not yet started a game in his college career. Despite his obvious talent, Epenesa was stuck behind veterans Parker Hesse and Anthony Nelson on the depth chart. It didn't stop him from leading the team in tackles for loss and sacks, though, and it has led to the expectation that there may be even more up his sleeve now that it will be his team in 2019.

Reason to Sell

While the limited playing time means there's potential for improved numbers, it also means we don't know yet if Epenesa has the endurance to be an every-down lineman. Through two seasons he has played every snap with an unparalleled degree of explosiveness, but that may be impossible to maintain as a starter.

Draft scouts will undoubtedly be looking to see if Epenesa starts taking plays off or runs out of gas in the second half of the season. If so, they'll either recommend Chase Young or a different position altogether for the top pick.

Justin Fields, QB, Ohio State

Eligible to Be Drafted: 2021

2018 Stats: 27-of-39 (69.2%), 328 yards, 4 TD, 0 INT, 173.7 rating; 42 carries, 266 yards, 4 TD

Reason to Buy

Throughout the entire recruiting cycle for the 2018 class, Justin Fields was neck-and-neck with Trevor Lawrence for the top spot, ending up with one of the best overall ratings (0.9998) in 247Sports composite history. He both ran circles around and threw bombs over the top of defenses in high school, and we have seen glimpses of both elite skills between his season at Georgia and his spring game at Ohio State.

His fit with Georgia—a run-first offense that hadn't had a quarterback rush for 200 yards in a season since D.J. Shockley in 2005—never made much sense, but this dual-threat QB should thrive in Columbus. J.T. Barrett threw for 35 touchdowns and rushed for 12 more in his final year with the Buckeyes (2017), and it wouldn't surprise anyone if Fields goes above and beyond those marks in either or both of the next two seasons.

Reason to Sell

We don't even have confirmation yet that Fields is a competent college quarterback, let alone a viable candidate as the best available quarterback two years from now. Yes, he was a stud in high school, but so were Davis Mills, Kyle Allen, Max Browne and plenty of other highly touted recruits who never came close to living up to the hype.

The numbers from Fields' brief stay at Georgia look nice, but they were primarily accumulated during blowouts of Austin Peay, Middle Tennessee and Massachusetts. In Georgia's other 11 games against "real" opponents, Fields was 9-of-15 for 73 yards with no passing touchdowns. We'll see how he fares as the main guy against Big Ten defenses.

Jake Fromm, QB, Georgia

Eligible to Be Drafted: 2020

2018 Stats: 207-of-307 (67.4%), 2,761 yards, 30 TD, 6 INT, 171.3 rating

Reason to Buy

Jake Fromm wasn't supposed to be the guy right away at Georgia, but a 2017 Week 1 injury to Jacob Eason forced Fromm into immediate action. Undaunted, he led the Bulldogs to back-to-back SEC Championship Games and one trip to the national championship.

Fromm was solid as a freshman, and he kicked it up a notch in year two with a 5-to-1 TD-INT ratio and impressive marks in completion percentage and yards per attempt (9.0). His season was a bit buried behind the higher volume and higher efficiency play of Tua Tagovailoa, Kyler Murray and Dwayne Haskins, but Fromm would've been a serious Heisman candidate in a more "normal" year for quarterbacks.

If he takes another step forward as a junior and goes through both Alabama and Clemson to get Georgia a title, there's a chance Fromm becomes the fifth quarterback in six seasons to go first overall.

Reason to Sell

Is he enough of a playmaker?

Fromm's efficiency is undeniable, but he has had the luxury of doing a lot of dinking and dunking in a run-first offense. In 29 games as Georgia's primary quarterback, Fromm has only completed 38 passes that went for 30 or more yards.

That doesn't mean he can't throw the deep ball. It just hasn't been asked of him often. He'll need to shine at the combine to have a shot at getting drafted before Tagovailoa or Trevor Lawrence, depending on whether he declares after this season.

Justin Herbert, QB, Oregon

Eligible to Be Drafted: 2020

2018 Stats: 240-of-404 (59.4%), 3,151 yards, 29 TD, 8 INT, 144.6 rating; 71 carries, 166 yards, 2 TD

Reason to Buy

Before we knew that A) Kyler Murray was committed to playing professional football and B) Justin Herbert was committed to another year at Oregon, most of the mock-drafting world had Herbert projected as the first quarterback off the board for the 2019 NFL draft. Barring an injury, he should be back in that mix again this year.

The 6'6" Duck with a big arm and both the legs and the pocket presence to stay out of trouble has all the tools you're hoping for in a franchise quarterback. He also led Oregon from four wins in his first season to seven as a sophomore, nine as a junior and the fringe of the preseason College Football Playoff conversation as a senior, which may make him even more attractive to what we can only assume is a rebuilding franchise making the first pick next April.

Reason to Sell

Herbert's draft-day highlight reel will be a thing of beauty. He has already put together some jaw-dropping moments with his ability to put the perfect touch on a fade route or to keep a play alive with his legs just long enough for something to open up downfield.

But consistency is the big question facing him for his final season. In nine of 13 games played last year, he had a sub-61 completion percentage. And unlike Josh Allen's run with Wyoming, we can't just chalk that up to a receiving corps with bricks for hands. He needs to make better reads in 2019.

Trevor Lawrence, QB, Clemson

Eligible to Be Drafted: 2021

2018 Stats: 259-of-397 (65.2%), 3,280 yards, 30 TD, 4 INT, 157.6 rating; 60 carries, 177 yards, 1 TD

Reason to Buy

Trevor Lawrence was every bit as good as advertised as a true freshman, leading Clemson to a national championship. He only threw four interceptions all season, never had multiple picks in a single game and didn't have any in his final five contests.

Lawrence was masterful in both games of the College Football Playoff, torching Notre Dame and Alabama for more than 300 yards and three scores. And with both Tee Higgins and Justyn Ross returning at wide receiver, we may see Lawrence unleash the deep ball even more often this coming season.

Reason to Sell

If the 2021 NFL draft were happening today, there's almost no question that Lawrence would be the first player selected. Two years is a long time to wait, though, and he is going to be the most scrutinized player in the country over the course of those two seasons.

If he and Clemson go 15-0 in both of those years, no problem. He'll be the No. 1 pick without a second thought. But if even minor warts (or injuries) begin to surface for one of the early favorites to win both the 2020 and 2021 Heisman, the NFL's worst team might be tempted to look elsewhere.

Walker Little, OT, Stanford

Eligible to Be Drafted: 2020

2018 Stats: N/A

Reason to Buy

Walker Little is quite big, which has caught the eyes of scouts for years. Listed at 6'7" and 313 pounds, Little was K.J. Costello's primary blindside protector in 2018 and will presumably reprise that role in the upcoming season. 247Sports had Little ranked as its No. 1 overall recruit in 2017. (The 247Sports composite had him at No. 9.)

Reason to Sell

Stanford's offensive line took a gigantic step backward this past season. Injuries were a big part of it—both to various linemen and to preseason Heisman front-runner Bryce Love—but the Cardinal went from 202.4 rushing yards per game in 2017 to a woeful 107.9 in 2018. Their rate of sacks allowed also ballooned more than 50 percent from 1.21 to 1.85 per game.

That obviously isn't entirely Little's fault. It probably wasn't his fault at all. But that degree of team-wide regression has to be a red flag for any franchise thinking about investing a No. 1 pick in this lineman. If Stanford doesn't have a bounce-back year on offense, Little may start sliding down draft boards.

Adrian Martinez, QB, Nebraska

Eligible to Be Drafted: 2021

2018 Stats: 224-of-347 (64.6%), 2,617 yards, 17 TD, 8 INT, 139.5 Rating; 140 carries, 629 yards, 8 TD

Reason to Buy

By making Baker Mayfield and Kyler Murray the top pick in the past two drafts, the NFL has shown it's not afraid to go all-in on a mobile quarterback. And if the team making the first pick in 2021 wants someone with a little more "escapeability" than Trevor Lawrence, Adrian Martinez might enter that conversation.

In just 11 games played, Martinez had seven games with at least 55 rushing yards. He also threw for at least 250 yards seven times and did so with uncommon accuracy.

Since the start of the 2016 season, the only other Power Five quarterbacks to rush for at least 550 yards, throw for at least 2,500 yards, complete at least 64 percent of passes and average at least 220 passing yards per game were Kyler Murray and Deshaun Watson—and they each did so as juniors, whereas Martinez did it as a true freshman.

If Nebraska does what most everyone is expecting and rallies from back-to-back 4-8 seasons to contend for the Big Ten title, even better for Martinez's draft stock.

Reason to Sell

Durability is a huge factor for NFL teams considering a dual-threat quarterback. And while Martinez (6'2") is bigger than both Mayfield (6'1") and Murray (5'10"), he suffered a leg injury in his first collegiate game and missed the subsequent one. If he misses any more time in the next two seasons, he'll end up with the dubious "injury risk" label.

Tua Tagovailoa, QB, Alabama

Eligible to Be Drafted: 2020

2018 Stats: 245-of-355 (69.0%), 3,966 yards, 43 TD, 6 INT, 199.4 rating; 57 carries, 190 yards, 5 TD

Reason to Buy

For the first two months before he got a little banged up and needed to start dealing with elite defenses, Tua Tagovailoa was unfathomably dominant. He had eight consecutive games with multiple passing touchdowns and no interceptions, entering November with a 238.8 QB rating. Before the first game against Louisville was even finished, it felt ridiculous that there was ever a question about whether he or Jalen Hurts deserved to start.

Despite the slightly bumpy finish between the SEC Championship against Georgia and national championship against Clemson, Tagovailoa posted the highest single-season QB rating in FBS history and was the runner-up for the Heisman. Things could obviously change, but he's the No. 1 quarterback on 2020 draft boards heading into the season.

Reason to Sell

The injury bug is the obvious top concern. Tagovailoa missed almost all of 2018 spring with a hand/finger injury before battling through knee and ankle issues throughout the regular season, culminating in ankle surgery following the SEC Championship. And already this summer there was a hamstring scare that kept him out of the Manning Passing Academy (he served as a camp counselor).

One other thing NFL franchises will need to consider with Tagovailoa is the fact that he's left-handed.

If he has another Heisman-worthy campaign and cements himself as the obvious top guy available, his handedness won't make a difference. But if there's even the slightest debate between Tagovailoa and a righty like Herbert, Fromm or Ehlinger, a team or two might pass on this lefty to avoid the possible negative effect it would have on the offensive line and the playbook as a whole. After all, there's not a single left-handed quarterback in the NFL right now.

Andrew Thomas, OT, Georgia

Eligible to Be Drafted: 2020

2018 Stats: N/A

Reason to Buy

Andrew Thomas started all 15 games at right tackle as a true freshman in 2017 and then made the transition to left tackle last season without missing a beat. He will presumably be drafted to protect an NFL quarterback's blind side, but it certainly doesn't hurt his marketability that he has anchored both ends of the line for a title contender.

Thomas is also a dual-threat in regard to run/pass protection. Not only has he done a fine job of keeping Jake Fromm clean in a conference loaded with elite pass-rushers, but he has helped Georgia produce four different 1,000-yard rushers over the past two seasons. That versatility makes Thomas the safe pick for first offensive lineman drafted in 2020—assuming he declares a year early.

Reason to Sell

Of the four players in the way-too-early mix for first offensive tackle drafted—Thomas, Walker Little, Trey Smith and Tristan Wirfs—Thomas is the smallest (6'5", 320 lbs). While size isn't the No. 1 factor in choosing a lineman, it does mean he needs to be that much more impressive than his peers during the predraft evaluation period.

Moreover, offensive linemen taken first or second overall in recent years weren't the answer those teams needed. Jake Long worked out quite nicely as the No. 1 pick in 2008, but Eric Fisher (No. 1 in 2013), Greg Robinson (No. 2 in 2014), Luke Joeckel (No. 2 in 2013), Jason Smith (No. 2 in 2009) and Robert Gallery (No. 2 in 2004) have combined for one Pro Bowl appearance (Fisher).

Even if Thomas is regarded as the best offensive lineman available, there hasn't been one taken in the top four overall picks in any of the past five years. Quarterbacks, defensive linemen and the occasional running back have been the primary targets lately.

Chase Young, DE, Ohio State

Eligible to Be Drafted: 2020

2018 Stats: 33 tackles, 14.5 tackles for loss, 9.5 sacks, five passes defended

Reason to Buy

At this point, it almost feels inevitable that someone from Ohio State will be drafted in the top four. Nick Bosa went No. 2 this past April, Denzel Ward was No. 4 in 2018 and Joey Bosa and Ezekiel Elliott went third and fourth, respectively, in 2016. The only other team to have multiple top-four picks in the past four years is Oklahoma (Baker Mayfield and Kyler Murray). Chase Young is a strong candidate to make it five top-four Buckeyes in five years.

Big things were expected from Young long before he got to Columbus, as he was rated the No. 7 overall recruit in the 2017 247Sports composite. But he impressed last year by thriving when "promoted" into the role of primary pass-rusher after the Buckeyes lost Bosa three games into the season. Young was outstanding in his first true test at Penn State (six tackles, 2.0 sacks, two passes defended), and he had three sacks and a forced fumble in the Big Ten Championship win over Northwestern.

Though he wasn't a full-time player until Week 4, he led Ohio State in both tackles for loss and sacks as a true sophomore.

Reason to Sell

If Ohio State's defense is as disappointing in 2019 as it was in 2018, that won't reflect well on Young.

The defensive linemen who have gone No. 1 overall in the past 15 years—Myles Garrett, Jadeveon Clowney and Mario Williams—played for schools that were clearly better on defense while they were on the roster.

In Young's case, he was the best player on a team that put forth its worst defensive effort in more than a decade. Meanwhile, Iowa's A.J. Epenesa thrived for one of the nation's stingiest defenses. When splitting hairs between those top two defensive linemen, that could be the deciding factor.

Kerry Miller covers college football and men's college basketball for Bleacher Report. You can follow him on Twitter, @kerrancejames. Recruit ratings courtesy of 247Sports' composite rankings.