If the 2017 NFL season has been defined by any one thing, it's likely the sub-par quality of play. 

When looking for root causes of that dip, it's obvious where to turn: the quarterbacks. While things like lack of practice time and the declining quality of offensive line play are partially to blame for the dreadful state of quarterbacking around the league, the drop-off in passer performance is much more noticeable and measurable. 

To wit: the league average passer rating in 2017 is 86.3, down from 87.6 last year and 88.4 the year before that. The league average in yards per pass attempt has also been dropping, from 7.3 to 7.2 to 7.1. 

But it's not just the actual play of (some) quarterbacks that has been bad in 2017. The teams themselves have made some outright terrible decisions when it comes to which quarterbacks are on their roster and which of them see the field, and when. Below, we'll get into some of the worst decisions NFL teams have made at the league's most important position throughout this season. In reverse order of terribleness ...

10. Patriots trade Jacoby Brissett for Phillip Dorsett

Brissett has emerged as a quality quarterback in Indianapolis while filling in for the injured Andrew Luck. He's completed 61 percent of his passes at 7.4 yards per attempt, thrown nine touchdowns against five interceptions, and run for an additional 154 yards and three scores. Dorsett, meanwhile, has been a non-factor in New England, even amidst various injuries to the pass-catching corps. He has only six catches for 101 yards and has not found the end zone. 

9. Dolphins give Jay Cutler $10 million to come out of retirement

Who would have thought that this would turn out badly? Jay Cutler knows Adam Gase's system! It's almost like a quarterback that elected to retire and was sitting naked on a porch while not at all preparing to become a color commentator did not actually have his head in the idea of playing football and came back only for the money. Cutler has been dreadful for the Dolphins, undermining their season almost as much as their defense has. 

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The Jay Cutler gamble has been a disaster for the Dolphins.  USATSI

8. Ravens stick with the Joe Flacco-Ryan Mallett depth chart

If you think Cutler has been bad, do yourself a favor and go look at Joe Flacco's numbers. He's worse across the board. If you took the name off the back of his jersey you'd be wondering why on earth Baltimore felt comfortable with him coming into the season, especially given the fact that he spent most of the offseason fighting an injury. Since the Ravens won the Super Bowl in 2012, there have been 32 quarterbacks to throw at least 1,000 passes. Flacco ranks 30th in touchdown rate, 27th in interception rate, 32nd in yards per attempt, and 31st in passer rating. He is just a bad quarterback and the Ravens sticking with him and an even worse backup may be the thing that holds them out of the playoffs. Given the quality of their defense, that's sad. 

7. Bills bench Tyrod Taylor for Nathan Peterman

This ... did not work out well. The Bills elected to send the quarterback with the lowest interception rate of all time to the bench, then saw his backup get picked off five times in the first half against the Chargers before mercifully pulling him from the game and letting Tyrod Taylor finish it out. It's not like Tyrod was lighting the world on fire before he was benched, but he certainly wasn't playing poorly enough to get the plug. It's not like it's his fault the Bills suddenly became unable to stop the run after trading Marcell Dareus. Not only did Buffalo lose a game's worth of ground in the playoff race with this decision, they may have done some damage to both Peterman and Taylor in the process. 

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Nathan Peterman's first start was historically awful.  USATSI

6. Packers roll with Brett Hundley after Aaron Rodgers' injury

Yikes has Hundley been terrible. He's got two games with three interceptions already, one less than Rodgers has in his whole career. Green Bay was 4-1 in the game when Hundley took over, and is now 5-5. It's one thing for the team to have confidence in its young backup filling in for a stretch while the all-world starter is on the sidelines, but it's another for the coach to get indignant about the idea of signing a free agent to add to the QB room -- the best available free agent, at that -- and then see the backup he was so high on come out and stink up the joint. It's hard not to believe the Packers could be in a better position right now with somebody else. It's not like the schedule has been outrageously difficult. 

5. Broncos decide Trevor Siemian, Brock Osweiler and Paxton Lynch are enough

Yeah ... this has not worked out great. John Elway and Vance Joseph can do all the offensive coordinator-firing they want, but the reason their offense can't do anything is because they do not have enough talent in the quarterback room. Siemian was alright last season and Lynch flashed enough ability at Memphis to be a first-round pick, so it was reasonable to enter camp with those two in competition with each other, but once neither player really distinguished themselves and Lynch got hurt, signing Osweiler -- fresh off one of the worst quarterback seasons in recent memory and such a bad camp that he got cut by the damn Browns -- was ridiculous at best and unconscionable at worst. Like the Ravens, they're undermining a good defense with poor QB play. 

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The Broncos are wasting a Super Bowl-caliber defense with terrible QB play again.  USATSI

4. Bears give Mike Glennon $15 million per year and stick with him for four weeks

Glennon last saw regular playing time in 2014. He was not very good. This is his age-28 season and he's been toiling on the bench for a few years, so the Bears decided that giving him $45 million over three years ($18.5 million guaranteed) was a good idea ... and then they traded up to No. 2 in the draft to select Mitchell Trubisky, who they promptly glued to the bench for the first four games of the year -- two of which Glennon basically lost single-handedly with his turnovers. It's not like the Bears were going anywhere special this year anyway, but this whole sequence of events could not have been handled any more poorly. 

3. Texans start Tom Savage over Deshaun Watson for Week 1, roll with Savage post-injury 

It's hard to believe that as recently as early September, Bill O'Brien thought Savage gave his team a better chance to win than Watson. He apparently wasn't too confident in his conviction, though, because he yanked Savage at halftime of the first game -- a game where he was sacked six times in 19 drop backs because the Texans' offensive line was a joke. Watson, of course, proceeded to take the league by storm over the next several weeks, only to tear his ACL in practice prior to Week 9. The Texans decided Savage was good enough to start and have stuck with him through a 1-2 stretch that has knocked them to the fringes of the playoff picture, while cycling through such ridiculous backup options as T.J. Yates, Matt McGloin, and Josh Johnson. Their rationalizations for signing those players over Colin Kaepernick, who could have slid in and run a similar offense to Watson, simply do not hold water.

NFL: Arizona Cardinals at Houston Texans
Tom Savage is taking the Texans nowhere.  USATSI

2. Browns pass on Watson, trade for Osweiler, name DeShone Kizer starter, bench Kizer for Kevin Hogan, bench Hogan for Kizer, try to trade multiple picks for AJ McCarron, forget to call in McCarron trade to league office, start the season 0-10. 

The Browns stay the Browns. 

1. Jaguars stick with Blake Bortles with a defense good enough to win a Super Bowl

This hasn't completely derailed the Jaguars yet, but it will. Bortles has shown nothing in his time under center that would suggest he is a quality quarterback. He hasn't been any good this season, and his play likely should have cost the Jags another win (the Chargers Chargers'd the game away because they're the Chargers). Imagine if this team had Tyrod Taylor or Colin Kaepernick or even Tony Romo. The floor would be so much higher for them without somebody that turns the ball over so much, and if they had someone with the ability to make plays and even win games himself, they'd be even better. The Jags have the league's best defense, one that is putting up numbers that only the Legion of Boom Seahawks and early 2000's Ravens and Buccaneers have approached in recent seasons. They should be a Super Bowl favorite. Instead, they're a fringe contender because you can't trust their offense. The Browns' disaster dance will affect them farther into the future, but for this year, the Jags not upgrading this spot is the single-worst QB decision in the league. 

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Two words why the Jags aren't winning a Super Bowl: Blake Bortles. USATSI