Projecting booms, busts among top 2017 QB prospects

There are no sure things in the NFL draft, but quarterback might be the riskiest position of all. No defense revolves around a single player the way every offense revolves around the quarterback. Trust your offense to the wrong young quarterback and your team isn't going to climb back into playoff contention. Recent history is littered with teams that drafted a quarterback high only to find out that player couldn't compete at the NFL level.

The lessons of history can at least help us figure out how much of a risk each quarterback prospect will be. That's the point of Football Outsiders' Quarterback-Adjusted-Stats-and-Experience (QBASE) projection system. It looks at college performance, experience and expected draft position (to incorporate scouting information that college stats will miss). To allow some time for development, QBASE projects a quarterback's efficiency (passing only) in years three through five of his career according to Football Outsiders' defense-adjusted yards above replacement (DYAR) metric. Fifty-thousand simulations produce a range of potential outcomes for each prospect, with players drafted later generally having a larger range of possibilities.

QBASE favors quarterbacks expected to go high in the draft who also have a relatively long résumé of college success according to the stats. Those stats include completion percentage, yards per attempt and team passing efficiency. These numbers are adjusted both for the quality of the defenses that a prospect had to face as well as the quality of his offensive teammates.

There has been a lot of debate about whether any quarterbacks will go in the top 10 picks of the 2017 draft, and QBASE suggests that none of this year's prospects really deserves to go that high. None of these players has a projection to match the best quarterbacks drafted in recent years. The highest-rated among them come with big questions about experience or about whether their college schemes affect our ability to translate college performance to the NFL.

One reason for this year's mediocre projections is that the top prospects of the 2017 draft did not lead the top passing offenses of the 2016 college season. College production isn't the only indicator of whether a quarterback translates to the NFL level, but usually the top-drafted quarterbacks have played for top-10 passing offenses according to Football Outsiders' Passing S&P+ ratings.

In 2014, for example, Oregon (Marcus Mariota) ranked fourth in Passing S&P+, while Florida State (Jameis Winston) was seventh. The year 2011 is another strong example, as Wisconsin (Russell Wilson) was No. 1, Baylor (Robert Griffin III) was No. 4 and Stanford (Andrew Luck) was No. 10. Cam Newton and Sam Bradford also led offenses that ranked No. 1 in Passing S&P+.

Only three of the top-10 passing offenses in 2016, however, were led by quarterbacks who are eligible for the 2017 NFL draft*:

*Note: This table leaves out Georgia Tech and Navy, as their passing ratings are the product of option offenses, for which pass plays tend to be successful because they are rare.

Zach Terrell isn't considered a serious NFL prospect, which leaves just Deshaun Watson and Joshua Dobbs in the top 10. North Carolina (Mitchell Trubisky) ranked No. 16 and Pittsburgh (Nathan Peterman) ranked No. 19, while this year's other top quarterback prospects all ranked below the top 20.

Every year, there are some draftniks who insist that next year is the really good year for quarterbacks, if teams are just willing to wait. Again and again, we hear this refrain only to see these young quarterbacks suffer in the eyes of the scouting community after another year of nitpicking. But this year, the "wait until next year" mantra for quarterbacks might be accurate.

Of course, it's hard to wait at the most important position in football. And there's still a good chance that at least a couple of this year's prospects will turn into reasonable NFL starters. Here are QBASE projections for eight quarterbacks that Scouts Inc. has rated among the top 120 players of the 2017 NFL draft:

Mitchell Trubisky, North Carolina

Scouts Inc. ranking: 29