Era-adjusted passer rating, and what we can take from Drew Lock's first two years

Note: Era-adjusted passer-rating figures involve measuring them relative to the average of the day: e.g. weighting Drew Lock’s figure against the 2019-20 league-wide rating of 91.7 that is the highest in NFL history, reflecting two decades of rapid rise that began in 2001.

John Elway has long displayed empathy for young quarterbacks finding their way in the sport — in large part because in the mid-1980s, he was in their shoes.

Those first two seasons of 1983 and 1984 for Elway saw magic — but also moments that could have driven onlookers to madness. During the 24 games he started during those two years, he threw 24 touchdown passes and 29 interceptions, posting a 67.0 passer rating.

Elway, of course, recovered. But his experience “drinking through a fire hose,” as he would often describe it, led to perhaps more patience with the quarterback than current, more favorable conditions might warrant.

Consider this: Elway’s era-adjusted passer rating in those first 24 starts in 1983 and 1984 is 57.7. That’s not great; it sits 9.0 rating points below the average era-adjusted rating of 66.7 (which was originally intended to be the average rating when the calculation was introduced).

But among 116 post-merger quarterbacks who made at least 15 starts in their first two years after being drafted or joining the NFL, Elway sits in the middle tier: 68th. Ahead of 48, behind 67.

(Note: This group does not include quarterbacks who had experience in other professional leagues such as the United States Football League, the Arena Football League and the Canadian football League.)

IF DREW LOCK WERE IN THAT SAME TERRITORY, he would not be out of danger in terms of how it impacts his long-term development.

Consider this: The five quarterbacks ahead of Elway in era-adjusted rating during their first two years of starting assignments are Kerry Collins, Steve Grogan, David Whitehurst and David Klinger.The five just behind the Duke of Denver are Rick Mirer, Richard Todd, Craig Erickson, Phil Simms and Matt Leinart.

That 10-QB sample size includes one Super Bowl winner (Simms), three more good long-term quarterbacks (Collins, Grogan and Todd) and six fringe starters or backups. Throwing Elway in there, the misses (six) outnumber the hits (five).

Now go down to Lock, whose era-adjusted passer rating of 54.1 places him 93rd among the 116-QB sample size.

The passers just ahead and behind Lock, along with their era-adjusted ratings:

• Mike Pagel, 1982-83: 55.1
• Gus Frerotte, 1994-95: 54.8
• Vince Young, 2006-07: 54.6
• Steve Walsh, 1989-90: 54.2
• Kyle Boller, 2003-04: 54.1
• Lock, 2019-20: 54.1
• Jim Zorn, 1976-77: 53.7
• Jack Trudeau, 1986-87: 53.6
• Josh Allen, 2019-20: 53.6
• Mark Sanchez, 2009-10: 53.4
• David Carr, 2002-03: 53.4

Those other just two long-term, solid-or-better starting quarterbacks; Allen and Zorn. The rest were fringe starters who eventually settled as backups.

That 1-in-5 chance is an improvement on the 1-in-7 chance of developing into a long-term starter that second-round quarterbacks like Lock have in the last 15 years.

Expand the territory to quarterbacks with era-adjusted passer ratings of 57.0 or lower in their first two years of starts, and you have a sample size of 40 passers, a group among which Lock sits 17th.

• Elite: 4 (Dan Fouts, Josh Allen, Troy Aikman, Terry Bradshaw)
• Good long-term starters: 5 (Doug Williams, Alex Smith, Steve Bartkowski, Dan Pastorini, Eli Manning)
• Mid-tier starters: 6 (Vinny Testaverde, Trent Dilfer, Chris Miller, Jim Zorn, Sam Bradford, Jim Everett)
• Fringe starters/eventual long-term backups: 23
• TBD: Lock, Sam Darnold

So, among the 38 quarterbacks with a clear outcome, that’s a 23.7-percent chance of finding a good-to-great long-term starting quarterback from a QB who started his career like Lock did … and a 60.5-percent chance that the quarterback is no more than a fringe starter.

Meanwhile, the odds of finding a viable long-term quarterback when selecting one in the first 12 picks is roughly 50 percent.

The Broncos will consider the extrinsic factors around Lock in the last two years as they come to their decision on how to add to the quarterback room. But they should also carefully weigh the long-term trends and how similar situations ended.

Like a good blackjack player, they need to know the odds and ensure that their choice is reasoned, and not from the gut or the heart.