Mel Kiper's Big Board for 2019 NFL draft: Top 25 prospects and position rankings

It's NFL combine week -- finally. I'm excited to get measurements and athletic testing numbers (especially the three-cone drill, my personal favorite) on every prospect in the 2019 draft. But I also want to see how the prospects interact with their peers. Who is going to emerge as a leader? Who is going to show confidence in everything he does? It's a great time of the year.

My updated Big Board rankings for the 2019 class are below, and I'm including my latest look at the top 10 prospects at every position.

My Mock Draft 2.0 was released last week, and we'll have full coverage of the combine on ESPN and ESPN.com. Let's start with the prospect who has been on top of my board since August:

Note: One asterisk denotes that the player is a junior, and two asterisks denote that the player was a redshirt sophomore in 2018.

Jump to the position rankings

1. Nick Bosa, DE, Ohio State*

Height: 6-foot-4 | Weight: 263 pounds | Previously: 1

There's no change at the top, as I've had Bosa to the Cardinals with the No. 1 pick in both of my mock drafts. He's expected to work out at the combine, and teams want to see that he has made a full recovery from the core muscle injury that ended his Ohio State career early. Bosa is an elite pass-rusher who is advanced for his age in his technique; you can probably thank his brother, Joey Bosa, and dad, John, both former first-round picks. He finished his college career with 17.5 sacks in two-plus seasons, most of which were in a loaded line rotation.

2. Quinnen Williams, DT, Alabama**

Height: 6-4 | Weight: 289 | Previously: 2

Williams was one of college football's best players -- not just defenders -- last season. And it showed, as he finished eighth in the Heisman Trophy voting. He dominated LSU with 2.5 sacks and 10 total tackles, and he finished the season with 8.0 sacks and 19.5 total tackles for loss. When I wrote about Williams after the LSU game, I mentioned his ability to use his hands to disengage from blockers. He is so good at destroying double-teams. Williams played only one full season for the Tide, but he was tremendous. He's the best 3-technique penetrator in this draft.