RB Leonard Fournette /Wesley Hitt/Getty Images

What does the NFL Scouting Combine mean to the draft stock of the players who will perform, those too injured to take part and even those not invited? Tons.

The combine, which ends Monday, is the best chance to compare athletes across the board. It's also the first chance for teams to meet underclassmen, put all 330 players through medical tests and conduct 15-minute private interview sessions. This is the introductory phase for these teams. Does the athleticism on the turf match what we saw on film? That's the question everyone will be asking throughout the week.

The NFL selects the best of the best and brings them all to Lucas Oil Field for a week of intense physical and mental testing. Who will leave Indianapolis with the most gained and lost? We'll take a look while also updating my top-400 rankings before the madness begins.

S Jamal Adams /Jonathan Bachman/Getty Images

Heading into the combine, it's worth noting that this is a really, really good draft class—and not just at the top with rare talents like Myles Garrett and Leonard Fournette either. This class is deep at multiple positions.

The 2017 safety and tight ends classes are the most talented I've ever seen. Jamal Adams and Malik Hooker are legitimately on par with Eric Berry and Earl Thomas as prospects. The same goes for the cornerback class with a legitimate eight players capable of going in the first round. Because of this, it's easy to want to put 50 players on a top-32 list.

When watching the workouts this week in Indianapolis, be aware of just how much talent is available at each spot. When I was coming up as a scout, we were taught to use the combine as a tiebreaker, and that's how I still view the event. Below you'll notice many players at the same position grouped together in the top 100 list. The combine will allow me to separate Corey Davis from Mike Williams or Marshon Lattimore from Quincy Wilson. The film grade I assign to players is ultimately around 90 percent of the final evaluation, but this is still a height-weight-speed league. Finding athletes matters.

Because of the depth of this class, there will be names below that will surprise you with where they're ranked. Some may seem too high, and some no doubt seem too low. Much will change in the next three months, but here's a look at the top 100 players for the 2017 NFL draft as we head into the combine.

Patrick Mahomes /David K Purdy/Getty Images

The big talk from media analysts—and I've been guilty of this too—is that the quarterback and offensive tackle classes are kind of weak. That's not fair. The quarterback class is incredibly deep. There just aren't day one starters like Jameis Winston or Andrew Luck. That doesn't make it a bad group; it's a group that isn't ripe yet.

Patrick Mahomes and DeShone Kizer have super rare traits. Mahomes has the strongest arm I've ever seen and is able to make unbelievable throws off-platform that few quarterbacks in the last 10 years of draft scouting have been able to. Kizer also has a strong arm and a big body, and he's a very good runner; he just needs time to develop.

Veteran scout Greg Gabriel told me a few weeks ago that "quarterback evaluation starts now," and he's right. So much of the final grade on a quarterback includes interviews, medicals, combine workouts, pro-day workouts and the wiring of the player. For Mahomes and Kizer, this week in Indy could shoot them to the top of my list.

Christian McCaffrey /Thearon W. Henderson/Getty Images

This is the year to get a running back. 

An unreal five running backs hold legitimate first-round grades, and many teams will eye this year as the time to get a young back. Leonard Fournette is a rare, generational athlete at the position and should turn heads in Indianapolis, but he's not the only top-tier back. Dalvin Cook and Christian McCaffrey both offer excellent three-down skills. So do Joe Mixon and Alvin Kamara, but concerns about off-field issues for Mixon could push him out of the draft completely, while Kamara saw limited use in two seasons as a backup at Tennessee.

There is value in this group on Day 2 and even into Day 3. There can be starting running backs to come out of this group in Round 4 or 5, much like a Jordan Howard last year. One interesting subplot to the draft will be if teams jump on running backs early or wait given the depth. Some general managers may see a player like Marlon Mack as a third-round value and potential starter and opt to pass on a Dalvin Cook in Round 1 because of that.

No matter where the run on backs starts in the draft, we can be confident there will be many of them drafted.

Corey Davis /Gregory Shamus/Getty Images

Corey Davis and Mike Williams might not be on the level that A.J. Green and Julio Jones were in the 2011 draft class, but we're seeing two very dynamic playmakers sit atop the board at wide receiver this year. After that, the depth is staggering too.

Williams and Davis are one-two on the board right now with time left for a flip-flop at the top. The combine will be big for both, but since Davis is struggling with an ankle injury, the on-field tests won't help push him over Williams just yet.

Among the favorites from the next tier, Carlos Henderson is a burner with great downfield ability, and possession guys like Cooper Kupp and Zay Jones have the skills to be instant starters in the pros. The same could be said for Chad Hansen, Chris Godwin and sleepers like Taywan Taylor.

There's a good chance three wide receivers go in the first round (Davis, Williams and John Ross) with a solid 10 possible on Day 2. With 31 receivers drafted last year and 35 the year before, that's a safe bet to look at in 2017.

O.J. Howard /Jamie Squire/Getty Images

Never before have I ranked two tight ends so high in a draft class. O.J. Howard and David Njoku aren't just special pass-catchers; both are special all-around players. This isn't an Eric Ebron-type pick. These are legitimate plug-and-play weapons with excellent blocking, receiving and run-after-catch talent. And both could be gone in the top 15.

Howard and Njoku are the cream of the crop, but this is a solid all-around group. Evan Engram and Jordan Leggett are very good flex tight end candidates, as is small-schooler Gerald Everett. Michigan star Jake Butt was considered a Day 2 prospect before suffering an ACL tear in the Orange Bowl, while Ashland junior Adam Shaheen is turning heads in pre-combine workouts.

Gauging pure athleticism is a great scouting tool for tight ends, and this group will put on a show in Indianapolis.

Ryan Ramczyk /Jerome Miron-USA TODAY Sports

All year we've talked about the lack of top-tier talent at the offensive tackle position. That hasn't changed—no player ranks inside my top 15—but the depth of the group is starting to impress with more viewings.

Garett Bolles and Ryan Ramczyk are battling for that first tackle slot, and what's interesting is that both players were one-year starters at their FBS schools—Bolles at Utah and Ramczyk at Wisconsin. Each shows remarkable movement and toughness, which could propel them up the board before the draft. Ramczyk, who had surgery on a torn hip labrum, will not work out at the combine.

After the Big Two, Cam Robinson is the next on the list. He's an excellent run-blocker but struggles with consistency and movement against smaller, quicker ends. The Alabama star will also need to answer questions about a summer arrest on gun charges when interviewed by teams.

The sleepers of the group come from Temple and Western Michigan. Dion Dawkins may end up playing guard in the NFL, but his ability to anchor and drive-block makes him exciting, while Taylor Moton is moving up my board consistently due to his plug-and-play skills as a right tackle.

Forrest LampJim Brown-USA TODAY Sports

While not a sexy position, offensive guard has become an important add in Round 1 of the NFL draft. Players like Zack Martin have helped round out offensive lines in Dallas, while Brandon Scherff was a top-five pick in 2015.

There aren't any top-five picks here, but there are some potential first-rounders. That starts with Forrest Lamp. The left tackle from Western Kentucky has the length of an NFL guard and projects well there given his excellent agility and poise as a blocker. Lamp, like Martin and Scherff, has all the tools to be a great day one guard after playing left tackle in college.

Other top names include Dan Feeney from Indiana and Dorian Johnson from Pitt. I've heard from NFL scouts that both players could rise into the top 50 picks due to the demand for solid offensive linemen in the NFL right now.

Everyone loves to watch linemen run the 40-yard dash, but I'll focus mostly on short-area agility drills like the three-cone and on-field work where players' movement and balance are on display. The 40 and the bench press are good for TV but haven't proved to be great indicators of NFL success.

Pat Elflein /Joe Robbins/Getty Images

Last year, Alabama's Ryan Kelly established himself as a legit Round 1 player. After the combine, all the talk in scouting circles was about him as a target for teams like the Indianapolis Colts and even the San Francisco 49ers in a trade-up scenario that ultimately netted Joshua Garnett. This year, there isn't a top-tier talent like Kelly, but two very good centers have the tools to make instant impacts.

Pat Elflein at Ohio State and Ethan Pocic from LSU are both impressive talents. Elflein is a shorter, more compact player, while Pocic is a hulking 6'6". While different in build, both are tough, nasty blockers who project as NFL starters.

After the two top players, the depth at center is equally impressive. Chad Wheeler and Tyler Orlosky could both be starting on NFL teams within two seasons and can be had after Day 2 of the draft.

We're accustomed to first-round centers after Kelly and Travis Frederick. While this year won't give us that top-tier draft pick, the depth is among the best in recent memory.

Jonathan Allen /Ronald Martinez/Getty Images

Alabama's Jonathan Allen is head and shoulders above the competition as the best defensive lineman in this year's class. That makes the combine important for him as he looks to maintain his status—and medicals will be huge for Allen given his string of shoulder surgeries in college—and also key for the players below him who are looking to come up the board.

The second tier of defensive linemen—Caleb Brantley, Montravius Adams, Malik McDowell and Elijah Qualls—combine impressive talents and tools but have question marks either about size, motor, wiring or scheme fit. McDowell, especially, is a gifted athlete in the mold of former first-rounder Arik Armstead and could see his stock rise in Indianapolis if he aces interviews with teams.

The real depth in this draft on defense comes at every position but defensive lineman, but there are plenty of diamond-in-the-rough prospects likely to be available in Round 3 or later. My favorite? Larry Ogunjobi of Charlotte, whose quick first step and stout build will remind many of Grady Jarrett.

Myles Garrett /Joe Robbins/Getty Images

The top overall player in the draft—Myles Garrett—headlines a stellar class of edge-rushers. While Garrett may be a generational athlete, there are legitimate seven pass-rushers with a top-32 grade, and a potential 10 of them could go in the first round when it's all said and done. That's unheard of.

Garrett should go first overall. Solomon Thomas could go top-five. Taco Charlton could go top-15. The top-tier talent is amazing, and the depth is also notable. If you can't find a pass-rusher in this class, fire your scouts.

What am I looking for from this group at the combine? As mentioned before, the drill work is a great tiebreaker. Looking at the cluster of players here—Takkarist McKinley, Ryan Anderson, Charles Harris, Derek Barnett—a leader can emerge as the top player in that group with what he does on the field and in meetings.

Edge-rushers aren't all about athleticism, but that is a very telling part of the evaluation. The 40 isn't a great scouting tool but does offer a cross-comparison among the players. As always, I find more value in three-cone drills, short shuttles and field work.

With 16 edge-rushers in the top 100, here's my list of the best overall.

Haason Reddick /Jonathan Bachman/Getty Images

Think back to all the great linebackers drafted early in Round 1 recently—players like Luke Kuechly and Patrick Willis. Reuben Foster has the tools to be a similar kind of player. While he wouldn't have ranked ahead of a healthy Jaylon Smith or Myles Jack last year—both were special players—he's still a very, very talented linebacker and worthy of a top pick.

Watching linebackers at the combine means focusing hard on change-of-direction skills and range, both as a tackler and as a cover man. Even middle linebackers nowadays are asked to cover the middle of the field, so Foster and those challenging for his top spot must show the ability to not only come up and play the run but also get deep in coverage.

The 2017 linebacker class is a very good one. Foster reigns as the king of the castle, but there are starters to be found outside the top 10 picks here. Haason Reddick's performance at the Senior Bowl has his stock soaring, and a good week of testing could secure his status as a Round 1 player.

Marshon Lattimore /Joe Robbins/Getty Images

NFL teams love cornerbacks, but in recent history they haven't drafted them super early. Patrick Peterson was the No. 5 overall pick in 2011, and last year Jalen Ramsey went in the same spot, but traditionally the first cornerback comes off the board around pick No. 10. This year, that won't be the case.

Marshon Lattimore is the man crush of many NFL scouts I've spoken to based on his size, speed and ball skills. Teams also like his teammate, Gareon Conley, and the duo at Florida (Teez Tabor, Quincy Wilson). Don't forget about Sidney Jones and Marlon Humphrey as potential Round 1 players either.

When April 27 finally gets here, a run on cornerbacks should be expected. The players mentioned above and USC's Adoree' Jackson are all contenders to hear their names called Thursday night.

It's not a top-heavy class, though. Starting-caliber cornerbacks can be found in subsequent rounds. There might be seven cornerbacks ranked in the first round, but there are another 10 ranked in the top three rounds after that.

Malik Hooker /Jamie Sabau/Getty Images

Not since the 2010 draft—when Eric Berry and Earl Thomas came out—has a draft class seen two safeties like Jamal Adams and Malik Hooker. Because of the rare talent the two possess, it's safe to assume NFL teams will be all over them in the early picks of Round 1.

Adams and Hooker are special, but they aren't alone in the Round 1 talk. Jabrill Peppers and Budda Baker are legitimate prospects and will warrant conversations after the combine given their athleticism. Peppers, especially, is poised to blow up in Indianapolis given his all-around skill set. He will work out as a linebacker, but I rank him among the safeties.

The strength of the safety class is at free safety with Day 2 prospects like Eddie Jackson, Marcus Williams and Justin Evans all potential starters. Like the edge-rusher class, no team should have an excuse to miss on a safety this year.