Back in the day, the measurables for quarterbacks were pretty simple — completion percentage, total yards and touchdowns thrown. Deep dives meant tacking on TD-to-INT ratio.

By those rudimentary standards, Mike Glennon isn’t all that bad. He’s completing 67.1 percent of his passes and has thrown for 514 yards, both good for 10th in the NFL. And, his two touchdowns against as many interceptions isn’t ideal, but you can live with it.

Based on those numbers, Glennon is somewhere in the middle of the pack of NFL quarterbacks, a spot perennially reserved for Jay Cutler.

So, why all the vitriol over the guy the Bears doled out $16 million to this season to lead them out of the Cutler era?

Here’s why.

When all the numbers and variables are crunched, NFL.com’s passer rating and ESPN’s total quarterback rating tell a drastically different story of Glennon’s first two starts.

Based on the traditional passer rating by the NFL, Glennon has an 81.2, placing him 21st among all starting quarterbacks.

And, according to ESPN’s total quarterback rating, which measures more of a passer’s overall game contributions, Glennon (32.3) is ranked 26th, one spot ahead of struggling Jaguars quarterback Blake Bortles.

Worse yet, in ESPN’s points-added category — something the Bears’ stagnant offense sorely needs — Glennon sits at -6.0. To simplify, Glennon’s overall contribution to the Bears’ offense this season has basically been a pick-6.

Only four starters in the NFL are worse than Glennon in the points-added category.

By comparison, Steelers quarterback Ben Roethlisberger, whom the Bears face on Sunday, leads the league with a +7.6. And, Falcons quarterback Matt Ryan, whom the Bears lost to in Week 1, is second with a +7.5.

Do I hear the Mitch Trubisky fan club screaming for more fodder? You got it.

In the most pedestrian measurable known to modern analytics — fantasy football — Glennon barely exists. No, seriously.

Fantasy Pros puts Glennon at No. 31, four spots ahead of Trubisky.

Sporting News ranks him dead last of the 32 starters.

But in the ESPN and SB Nation rankings, which each go 27 deep, Glennon is nowhere to be found.

Fantasy players know the truth about Glennon. When does reality set in for the Bears?

Follow me on Twitter @dancahill_cst