Mel Kiper Jr. says the Broncos would be most likely to trade down in the draft with the Bills as a potential partner. (0:38)

The 2018 NFL draft is here -- and now we can finally figure out where all of these quarterbacks are going.

Below are my "final" Big Board and "final" position rankings for the class of 2018. I'm putting "final" in quotation marks because I'll be making a few tweaks up until the draft begins (Thursday at 8 p.m. ET on ESPN and the ESPN app, in case you were wondering). I'll be talking to more sources and adjusting my rankings based on what I hear. And remember, my Big Board is not a prediction of where prospects will be drafted, only where I have them ranked.

Notable: My Big Board goes to 300 prospects, and my position rankings cover more than 700. But it's important to note that the cutoff for undrafted free agents starts around 35 for positions like wide receiver. That means approximately 90 wide receivers have grades that are nearly identical. In short: Players ranked from 150 to 250 on my board are similar. It's splitting hairs.

Click the links below to go to each section:

Top 300

1-25 | 26-50 | 51-75 | 76-100

101-150 | 151-200 | 201-250 | 251-300

Position rankings

Offense: QB | RB | FB | WR | TE | OT | G | C

Defense: DE | DT | ILB | OLB | CB | S | K | P | LS

1. Saquon Barkley, RB, Penn State

Previous rank: 1

Barkley is the best prospect in this draft. His testing numbers at the combine -- 4.40 40-yard dash and 41-inch vertical -- were elite at any size, much less a 6-foot, 233-pound back. Barkley plays with tremendous balance, a great lower body and quick feet. He's a stellar runner both inside and outside the tackles, and he showed in 2017 that he's a true three-down back. He had 54 catches after having 48 combined in his first two seasons at Penn State. Barkley is a special talent.

2. Bradley Chubb, DE, NC State

Previous rank: 2

Chubb could have entered the 2017 draft and been in the first-round discussion. At 6-4, 269 pounds, he shows good takeoff from the edge, and he has an excellent mix of speed and power. You saw some of that speed and explosion at the combine, where he ran a 4.65 40 and had a 36-inch vertical. Chubb had 10 sacks and 25 tackles for loss (tied for second in the FBS) in 2017 and had 10 sacks and 21.5 tackles for loss in 2016. Chubb doesn't have quite as high of a grade as Myles Garrett did last year, but he's in that same tier.

3. Roquan Smith, ILB, Georgia

Previous rank: 4

Smith is getting buzz as a potential top-eight pick. His tape is too good, and he's too athletic -- he ran a 4.51 40 at the combine -- for teams to be worried as much about his size (6-0, 237). He can get sideline to sideline in a hurry. A season after recording 95 total tackles and five tackles for loss, Smith had 137 tackles, 14 tackles for loss and 6.5 sacks in 2017. He can blitz up the middle or off the edge, and I think he could play inside or outside linebacker. He's just a fun player to watch, and he was one of the best players on the field in both of the Bulldogs' College Football Playoff matchups.

4. Quenton Nelson, G, Notre Dame

Previous rank: 3

Nelson and Mike McGlinchey formed the best left side of an O-line in college football. Nelson has a chance to go in the top five, and I don't think he drops past Chicago at No. 8. At 6-5, 335 pounds, Nelson causes destruction in the interior. I wrote last year that he was entertaining to watch, and you just don't say that about guards. He is a dominant run-blocker who is powerful at the point of attack and athletic enough to pull and get into space.

5. Josh Allen, QB, Wyoming

Previous rank: 5

Allen has crushed the pre-draft process and is in the mix to be the No. 1 overall pick. He has shown improvement at the Senior Bowl and at the combine, and he has a high ceiling. Allen (6-5, 237) is super raw but can really sling it. His numbers weren't great in 2016 (28 touchdown passes, 15 interceptions while completing 56 percent of his passes), and his numbers weren't great in 2017 (16 touchdown passes, six interceptions while completing 56.3 percent of his passes), but NFL teams will take into account the talent around him. The Wyoming offense lost 47 touchdowns from the 2016 team, along with its center. I think Allen's numbers will be much better in an NFL offense with NFL players. He put some strong film together in the Cowboys' bowl win, throwing three touchdown passes in the first half, even while recovering from a shoulder injury.