A whopping 48 quarterbacks have taken the field during the regular season.
First-string passers are lost every year, but this campaign has been marked by a handful of backups who have stepped in and made a difference. In some cases, guys who were nobodies in September have materialized as better options than the men they replaced.
Here's a look at four signal-callers who have captured our attention in 2013:
Kubiak argued his young passer was struggling with in-game audibles against the Oakland blitz, but Keenum showed well against Kansas City's pass rush and Arizona's aggressive front. Why yank him against the Raiders?
The positives are clear: Keenum shows a fearlessness winging the ball downfield. Pro Bowl receiver Andre Johnson hadn't scored a touchdown all season with vanilla Matt Schaub at the controls, but Keenum found him for five scores over a two-game span.
It's unfair to expect perfection from a quarterback after four starts. Keenum has struggled at times with ball security, but he's made plays facing a higher percentage of pressure on his 141 dropbacks than any passer in the league, according to Pro Football Focus. Keenum's flung eight touchdown passes to only one pick along the way and shown a knack for escapability that Schaub can only fantasize about:
It hasn't been an easy stretch for Kubiak, but he did more harm than good pulling Keenum, who we see a viable quarterback of the future in Houston.
"You know what, some of these guys just have it," said coach Dennis Allen. "Do you know what I mean? ... There's something deep down inside of them, that they don't pay any attention to the fact that people say they can't do it."
We should have seen this one coming. Despite the emergence of Terrelle Pryor, the Raiders have been "intrigued" by McGloin for months, and NFL Network's Charley Casserly argued in September that the former Penn Stater threw the ball better than any other Raider at training camp.
McGloin's arm is livelier than Pryor's and -- not unlike Keenum -- his knack for finding targets downfield expands the scope of Oakland's offense. His 18 completions included four strikes of 20-plus yards, including this pretty 26-yarder to Mychal Rivera:
NFL Media columnist Michael Silver expected the Raiders to stick with the "hot hand" under center, and that's exactly what they're doing. It's another sign of how quickly things can change at the position.
This season's Chicago Bears are a classic example of what sound coaching can do for your starter ... and the guys behind him.
It was evident when McCown stepped in for Jay Cutler in a Week 7 loss to the Washington Redskins that coach Marc Trestman had full confidence in his No. 2. The game plan didn't change, but McCown had.
Crisp passes, quick decisions, good pocket movement and production downfield have characterized his play over four appearances. McCown's numbers -- five touchdown passes, zero picks and a completion percentage of 60 percent -- speak to the passer's strong in-game choices. On a rain-soaked, battered field against the Ravens, McCown delivered:
Hitching your wagon to a 34-year-old career backup doesn't make long-term sense, but we'll find out how Trestman truly feels about his starter when Cutler's contract expires after the season. The bigger takeaway here? Chicago arguably has hired the best passing teacher in the NFL.
Tolzien's outing Sunday against the Giants showed more of the same, but the young quarterback has accounted for 619 yards over two weeks. His ratio of one touchdown to five picks has cost Green Bay, but coach Mike McCarthy was impressed with Tolzien's aggressiveness:
"I'll say this, our big-play production -- nine explosive plays on offense -- I have never seen a quarterback hit all his big throws like that in a game," McCarthy said, per the Milwaukee Journal Sentinel. "That was the most impressive big-play, big-pass play production from a quarterback. ... I was talking to Scott and going through his grading session this morning and I can't think of another time in my career that I've had someone hit every one."
This from a guy who's spent his Packers career with Brett Favre and Aaron Rodgers. Tolzien has struggled with some bad reads and a lack of vision, but he's not afraid to take shots. He displayed chemistry with Jarrett Boykin last week and again Sunday, with this 52-yarder:
The Packers desperately need a win, something Tolzien hasn't delivered, but they've found a young passer to groom. That alone makes him a better option than Seneca Wallace.