The underwear Olympics are here.

This week in Indianapolis, over 300 of the best and brightest players in college football will gather to be put through the paces by scouts and coaches from across the NFL. They will be measured, examined and interviewed before taking part in drills designed to test their strength, speed and agility.

In recent years, the NFL Scouting Combine has become a media event—and it's a week that has a massive impact on a prospect's draft stock.

Every one of the youngsters in Indy has something to prove. For some, it's a matter of shoring up their status as Day 1 picks. For others, it's showing that their strengths offset perceived weaknesses. Others are trying to show that they are healthy and ready to start their professional careers.

Of course, some players have more to prove than others. Maybe it's establishing themselves as the cream of the crop at their positions. Or showing that they're more than what they've been perceived as. Or that a small-school star can play with the big boys.

For these players, the stakes are high. There's much to prove. And potentially even more to lose.

Nick Bosa, EDGE, Ohio State

Admit it—you were expecting to see a quarterback first.

Don't worry, we'll get to those in just a second.

But first, there's the matter of the player who could be drafted ahead of all of them.

There's no questioning Nick Bosa's talent. In 2017, his last full season, the 6'4", 263-pound edge-rusher racked up 8.5 sacks and 16 tackles for loss. There are those in the scouting community who believe that Bosa may be a better prospect than his brother, Joey, who went third overall in 2016 and went on to be named the Defensive Rookie of the Year.

But Bosa made it just three games into the 2018 campaign before suffering a core muscle injury that required surgery. Rather than risk reinjury by coming back late in the year, Bosa withdrew from Ohio State in order to prepare for April's draft.

It's been a good long while since we saw Bosa in action—even in drills.

As Matt Maiocco reported for NBC Sports Bay Area, Bosa's father, John, indicated that his younger son will be a full participant in Indianapolis:

"If there's anything he feels he'd like to re-test, then he'll go to the Ohio State pro day and re-rest there. But I'm pretty sure he's going to be pleased with everything he does at the combine. His training was a combination of rehab and training. Health-wise, as of about three weeks ago, now it's 100 percent training for the combine. So he's 100 percent healthy and ready to go."

If Bosa can show he's none the worse for wear after that lost season, his hold on the No. 1 overall pick will strengthen. But if red flags pop up, that grip's going to get shaky.

Dwayne Haskins, QB, Ohio State

Might as well stick with the men from Columbus.

The general consensus among most in the draftnik community is that the top two quarterback propects in the class of 2019 are Ohio State's Dwayne Haskins and Oklahoma's Kyler Murray. Those young signal-callers share a couple of things in common. Both were just one-year starters in college.

And since both are underclassmen, they weren't in Mobile, Alabama, for the Senior Bowl in January. The combine will be many scouts' first extended in-person look at the pair.

And, boy oh boy, are people going to be looking.

In recent years, it's become more and more common for some of the top quarterback prospects to skip throwing in Indianapolis, instead preferring the more controlled environment of their pro days. USC product Sam Darnold did so last year.

To his credit, Haskins has declared his intention to participate in all activities at the combine, per ESPN.com.

But that could be a double-edged sword. If Haskins shows off the strong arm and pinpoint accuracy he displayed so often at Ohio State, it will help to solidify his status as the top prospect at the NFL's most important position.

But if he has an off day, the whispers are going to start, and the door could be open for a guy like Murray to surge past Haskins.

Kyler Murray, QB, Oklahoma

There likely isn't going to be a more talked-about player at the combine than Oklahoma's Kyler Murray. And as Bleacher Report's Matt Miller pointed out, that's before we even know how much Murray's going to do:

"Every team with a need at quarterback—and even some of those just thinking about an upgrade—will wonder the same thing: Will Murray throw in front of scouts at Lucas Oil Stadium? Will he lace up his cleats and run the 40-yard dash—a stretch of grass he says he's covered in 4.3 seconds previously? Or will Murray show up, get measured, take his interviews and go home?"

Even if the 2018 Heisman Trophy winner just shows up, gets measured, interviewed, smiles for the cameras and then bolts, he's going to have as much to prove as any prospect.

There isn't a player with more riding on measurements than Murray. We know that he is undersized by NFL quarterback standards—and then some. If he comes in any smaller than the 5'10" and 195 pounds he's listed at, eyebrows are going to go up.

There's also the matter of the interviews. Murray has stated more than once that he's 100 percent dedicated to his football career—per Jeremy Bergman of NFL.com, Murray did so again last week. But it's a safe bet every interview is going to contain a query along the lines of, "So, you like baseball, huh?"

Tyree Jackson, QB, Buffalo

OK, just one more quarterback—promise.

In January, Buffalo Bulls signal-caller Tyree Jackson was one of the early stars of the Senior Bowl.

That's what happens when a quarterback checks in at 6'7" and 249 pounds, with 10-inch hands, 35-inch arms and an 82½-inch wingspan, per Optimum Scouting.

That's not a quarterback—it's a good-sized tight end.

There was a problem, though. The week continued after the weigh-in, and while Jackson has a big arm, his accuracy and progressions left a lot to be desired.

None of that was especially revealing. It was no secret that Jackson is a raw prospect who barely completed 55 percent of his passes in 2018.

But that means the combine is important for the big prospect with the big arm.

If Jackson fares well in athletic drills and while throwing the football, that could go a long way toward convincing teams he just needs the right coaches and that most mythical of pro concepts: development.

But if Jackson doesn't test as well as expected and/or struggles as a passer, it's just going to reinforce the negatives that were evident in Mobile.

If there's one thing working in Jackson's favor, it's that NFL teams are like nine-year-olds at Christmas with quarterbacks. There's some skepticism, to be sure—but they want to believe.

That's how Paxton Lynch would up being a first-round pick in 2016.

Of course, teams know how that worked out. So Jackson has little margin for error.

D.K. Metcalf, WR, Ole Miss

The Baltimore Ravens are among a number of teams that could take a long look at a wide receiver in Round 1. Per Clifton Brown of the team's official website, Ravens Director of College Scouting Joe Hortiz likes the depth at the position.

"It's a pretty deep group," he said. "Top-tier, I think everyone is going to probably have different guys at the top. ... There are guys in the first, second, third rounds that are going to have a chance to come in and be starters in the NFL."

D.K. Metcalf of Ole Miss is among those high-end wideouts and is riding a wave of buzz into Indianapolis after a photo emerged of him looking—let's go with ripped.

Actually, ripped doesn't do it justice.

While the 6'4" Metcalf looks like he could wrestle a bear (and win), Hortiz noted there could be a down side to all that weightlifting.

"You can be too muscular at any position if it prohibits your flexibility," Hortiz said. "If he goes out and looks flexible still, which I expect him to be because he's a really athletic kid, I think he'll be fine."

Flexibility isn't the only trait Metcalf will need to display. After a neck injury cut short his 2018 season, his medicals will be of great interest.

And as is the case with all the wideouts, a lot of eyes will be on Metcalf (who isn't known as a burner) when he runs the 40-yard dash.

A sluggish one could knock him down a crowded pecking order at wideout. And out of Day 1.

Mike Weber, RB, Ohio State

After sharing the workload with J.K. Dobbins at Ohio State in each of the past two seasons, Mike Weber isn't a running back who's generating a ton of draft hype. On Matt Miller's latest big board, Weber—who rushed for 954 yards and five scores in 2018—is the 11th-ranked tailback.

The reason for that pedestrian ranking? As Trevor Sikkema of the Draft Network pointed out, Weber isn't perceived as especially explosive.

"Even though he's improved as a runner in many areas," Sikkema wrote, "that area is still a limitation of his—likely just because speed is often something that can't be taught or improved upon very much once you get to his point of a career."

However, Weber showed flashes at Ohio State with long runs here and there in which he appeared to find that last gear. If the 5'10", 214-pounder runs well at the combine, scouts are going to go back to the film room, and they will find a back who does just about everything well, whether it's running between the tackles, catching the ball out of the backfield or picking up the blitz.

There's a reason Weber is Miller's biggest sleeper at the position. And a reason Weber could sneak into Day 2 of the draft—a day that has produced a lot of value in the backfield in recent years.

If Weber falters in the 40-yard dash, though, he'll be locked in as a Day 3 JAG ("just a guy") pick. As such, there may not be a player at the position with more on the line at the combine.

No more Buckeyes after this. Promise.

Deandre Baker, CB, Georgia

Georgia Bulldogs cornerback Deandre Baker is one of the top prospects at his position, and that isn't in question. After racking up 40 tackles and two interceptions in the SEC, the toughest conference in college football, Baker was awarded the Jim Thorpe Award as the best defensive back.

Baker isn't short on confidence either. While speaking with Brooke Cersosimo of NFL.com, Baker said that Deion Sanders was "the best to do it before me" and predicted that he's going to blow the roof off Lucas Oil Stadium.

He didn't give a prediction for his 40-yard dash, though. He doesn't want to scare people.

"Every part of the combine, [I want to] be the best at each drill," he said. "I don't want to put a number out there [for the 40-yard dash] just yet. I don't want to scare nobody. Just watch and see."

The thing is, if Baker's going to leapfrog players like LSU's Greedy Williams, he's going to have to do just that—test through the roof in the 40 and agility drills.

As athletic and as talented as Baker might be, he's not especially big at 5'11" and 185 pounds. That has raised some questions about his ability to hang in there against big-bodied receivers on the outside.

The faster and more fluid in transition that Baker is, the less NFL teams are going to care that he's a bit on the small side—and the better his chances of being selected in the first round April 25 in Nashville, Tennessee.

Deebo Samuel, WR, South Carolina

I'm going to resist the urge to make any remarks about bicycles, chains purchased by grandmothers and fistfights with neighbors named Craig.

Besides, South Carolina wide receiver Deebo Samuel appears to be well on his way to becoming better known that any fictional neighborhood bully.

The 6'0", 210-pound Samuel, who hauled in 62 passes for 882 yards and 11 touchdowns for the Gamecocks in 2018, was the star of January's Senior Bowl. Samuel got open at will and showed excellent burst, route running and hands.

There wasn't a player who was more impressive in Mobile.

As Josh Kendall noted in The State, ESPN NFL draft analyst Mel Kiper Jr. thinks Samuel could work his way into the first round.

"He's right in the mix to be a solid early to mid-second rounder," Kiper said. "I wouldn't count out late one. He's got great versatility; he's got great explosiveness. I would say he doesn't get past, at worst, the end of the second round."

Sure enough, there have been some mock drafts of late that have Samuel sliding into the latter stages of Round 1.

If Samuel has the kind of week in Indiana that he did in Alabama (or even relatively close), the number of those mock drafts with Samuel going early is going to spike right alongside his draft stock.

However, if he falters, that momentum could vanish as quickly as it arrived.

Alex Bars, OG, Notre Dame

It might seem a bit odd to point to someone who won't even be working out as one of the players with the most to prove at the combine.

It's been that kind of year for Notre Dame guard Alex Bars.

The 6'6", 315-pound Bars entered the 2018 campaign as a team captain and one of the top guard prospects in the country at a school that cranks out NFL-caliber linemen like Taco Bell cranks out bad food.

But everything changed in an early-season game against Stanford, when Bars tore the ACL and MCL in his left knee.

That injury that will preclude Bars from working out at the combine, but he told Tim Prister of 247Sports he's looking forward to making an impression:

"I won't do any drill work. It will be interviews and all the medical testing. The medical testing obviously is the most important thing. My leg will do phenomenal there. I'm not really worried about it. They'll poke and prod just to make sure it will be healthy come fall. Full flexion, full extension…the muscle is there. Whatever they want to do, it's healthy."

Bars should do just fine in interviews—he's an experienced player who has played on both sides of the line. If the medical checks go as well as Bars expects, there are going to be teams who will see him less as an injured player and more as a potential value.

If they don't?

Bars is going to be waiting until Day 3 to hear his name called.

Terrill Hanks, LB, New Mexico State

After starring at South Carolina State, linebacker Darius Leonard went from a small-school standout to a combine star to a second-round pick of the Indianapolis Colts to leading the NFL in tackles and winning 2018 Defensive Rookie of the Year honors.

That performance will likely have teams looking that much harder at small-school stars this year—stars like New Mexico State linebacker Terrill Hanks.

Like Deebo Samuel, Hanks tore up practices at the Senior Bowl, evoking comparisons to the aforementioned Leonard from Daniel Jeremiah of NFL.com.

"His speed has jumped out in both of his practices this week," Jeremiah said. "I see some similarities to Colts All-Pro rookie Darius Leonard in terms of production and body type. Leonard's rise began at the Senior Bowl last year, and Hanks is picking up where Leonard left off here in Mobile."

In today's NFL, success at the linebacker position is all about speed and range—the ability to roam sideline-to-sideline and cover backs and tight ends in the passing game. Leonard demonstrated those wheels last year in Mobile. Then in Indianapolis. Then in, well, Indianapolis again.

If the 6'3", 235-pound Hanks, who topped 100 total tackles for the Aggies in each of the last three seasons, continues along the same path by testing well in drills and posting a solid 40 time, it would go a long way toward cementing his status as a Day 2 pick—and a potential steal.  

On the other hand, if he falters, it's going to be much more difficult for a team to justify spending significant draft capital on a player whose level of competition in college was...less than imposing.