One question that the Broncos must answer in the midst of their decisions regarding quarterback Drew Lock is this: Does his improvement down the stretch last season warrant sticking with him for another year?

By the numbers, the discussion starts with Lock’s passer rating. In his final six starts of the 2020 season, he posted an 85.7 rating — 10.0 points higher than the mark he notched in his first 12 career starts.

That improvement ranks 48th of 145 quarterbacks to have made their first 18 starts at some point since 1990, according to the data compiled by pro-football-reference.com.

These are the quarterbacks in the same general range of improvement as lock — with a rating improvement of 8.0 to 12.0 points from their first 12 starts to their next six:

• Andrew Luck, 2012-13: plus-8.4
• Kyle Boller, 2003-04: plus-8.6
• Jay Cutler, 2006-07: plus-9.8
• J.P. Losman, 2005-06: plus-10.3
• Chad Henne, 2009-10: plus-10.4
• Trent Green, 2008-10: plus-10.7
• Derek Carr, 2014-15: plus-11.8
• Stan Humphries, 1990-92: plus-11.9
• Blake Bortles, 2014-15: plus-11.9

To quote Lloyd Christmas, “So you’re telling me there’s a chance.”

But it’s not one-in-a-million. Five of those nine quarterbacks eventually developed into viable, long-term starters — although two of those five had their careers cut short by injuries (Luck and Humphries).

Still, there is something else to consider here in the Broncos’ decision-making process: None of those quarterbacks hit an elite tier. Luck had all the tools that a quarterback could possess, but did not have the other tool even the elite passers need: proper protection to keep him upright.

The others who became long-term franchise quarterbacks from this group — Cutler, Green, Carr and Humphries — were in the second or third tier of quarterbacks, with Green in his era being the best of that group, especially for the 2002-05 stretch when he ran Dick Vermeil’s offense to near-perfection in an ideal marriage of scheme and passer.

Also, note what happens when you consider the era-adjusted passer ratings for these quarterbacks (adjusted relative to the average of their time frame, with the mean being the originally intended 66.7 rating):

• Green, 2008-10: 81.0
• Cutler, 2006-07: 80.9
• Humphries, 1990-92: 70.4
• Henne, 2009-10: 69.4
• Losman, 2005-06: 67.3
• Luck, 2012-13: 65.4
• Carr, 2014-15: 63.3
• Lock, 2019-20: 60.5
• Bortles, 2014-15: 59.1
• Boller, 2003-04: 55.8

It’s better to be near the top, but Carr and Luck offer hope that a below-mean adjusted rating in starts 13-18 doesn’t necessarily derail you.

While Lock’s overall second-season production places him firmly in the danger zone from which there are far more misses than hits, his rating from his final six starts puts him in another category. That is one in which there is an even-money shot of becoming a solid starter who — with the right circumstances and surrounding talent — has a chance to guide a team to success when everything breaks right.

But is that enough?

Can Lock potentially improve like Carr did?

The answers could weigh heavily into the Broncos’ decisions regarding Lock and a potential veteran addition at the game’s most important position.