Mel Kiper's preseason Big Board: Ranking top 2018 prospects

QBs make up Kiper's top 3 in 2018 draft (1:25)

Mel Kiper's Preseason Draft Big Board has quarterbacks Sam Darnold, Josh Allen and Josh Rosen as the top three draft choices. (1:25)

Did you miss me? Studying NFL draft prospects never stops, of course, but I'm back from my summer vacation armed with an updated Big Board for the 2018 draft.

My way-too-early top 25 for this draft class came out in May, and this edition brings a few prospects moving up and down the board, plus some making their debuts.

A few notes before we get started:

  • The write-ups here won't change much from my way-too-early Big Board. Only a few games have been played so far, so I'm still waiting to see who has taken a step forward since last season.

  • Keep in mind that several prospects here have started only one season, so my projections are based on size, athletic ability, statistics and what I hear from people around the league.

  • Speaking of sizes, what's listed here is what schools give out. These could vary greatly when players show up at the NFL combine. True height and weight really matters for almost every position.

All right, let's get to it. Oh, and check out Todd McShay's first top 32 here, and get ready for our weekly college football stories.

Note: One asterisk denotes player is a junior, and two asterisks denote player is a redshirt sophomore for the 2017 season.

1. **Sam Darnold, QB, Southern California

Darnold has everything that NFL teams want in a starter. He has a big frame (6-foot-4, 225 pounds), makes quick decisions and is an accurate and natural passer. He completed 67.2 percent of his passes last season and ranked second in the nation in Total QBR (86.8). Darnold has an unorthodox, long delivery, however, that will have to be retooled. And the third-year sophomore has started only 10 games. I'm excited to see him in his second season as a starter, and he has two tough games in the first month of the season -- at home against Stanford and Texas.

2. *Josh Allen, QB, Wyoming

The buzz around the 6-5, 233-pound Allen just keeps growing. Now everyone wants to see him play. He can really sling it. Allen's numbers weren't great last season -- 28 touchdown passes, 15 interceptions while completing 56 percent of his passes -- but NFL teams will take into account the talent around him. And Wyoming also lost a few offensive players to the NFL after last season. Allen is raw but talented, and he'll get a big test from Iowa in Week 1.