Mobile quarterbacks bring the excitement to college football, but the ability to throw the ball accurately to every area of the field will always be the most coveted trait in a signal-caller.

We're looking at the best pure passers who are returning to the college ranks in 2017.

To be clear, this isn't an overall quarterback ranking. Otherwise, talented players like Jalen Hurts, Trace McSorley, Quinton Flowers, J.T. Barrett and Jake Browning would also be spotlighted.

Except for not including prospects who signed in 2017, age had no effect on the rankings. Sample size mattered, but each quarterback has been a starter for at least a majority of one season.

10. Austin Allen, Arkansas

By the numbers: Last season, Austin Allen replaced his brother, Brandon, as the full-time starter for Arkansas. The younger sibling posted a 61.1 completion percentage for 3,430 yards and 25 touchdowns, finishing 7-6 on the year.

Why he's here: When afforded time in the pocket, he's a highly accurate passer. Unfortunately for Allen, the offensive line was a sieve in 2016. Opposite Alabama, for example, the Tide pressured him on 42 of 61 dropbacks, per Pro Football Focus. The lack of protection shouldn't overshadow Allen's ability to throw.

Biggest tests in 2017: The SEC West brings a gauntlet for Allen, but no matchups are tougher than Alabama and LSU. Constant pressure from the front seven may frustrate the 22-year-old, who tossed five interceptions against those defenses last year.

9. Brent Stockstill, Middle Tennessee

By the numbers: Over the last two seasons, Brent Stockstill has passed for 7,238 yards and 61 touchdowns while tossing just 16 interceptions. Impressively, the southpaw connected on 64.9 percent of his third-down attempts in 2016.

Why he's here: Stockstill is an accurate passer to every level of the field, though it helps to have a standout target like Richie James on the receiving end. Nevertheless, the QB has showed exemplary touch on passes downfield and to the sideline.

Biggest tests in 2017: Middle Tennessee faces a challenging nonconference slate with Vanderbilt and road trips to Syracuse and Minnesota in early September. In conference play, Stockstill's biggest obstacles will be Western Kentucky and Old Dominion.

8. Luke Falk, Washington State

By the numbers: Luke Falk has been an ideal distributor for Mike Leach's Air Raid attack. Since the beginning of the 2015 season, he has completed 69.7 percent of his 1,277 attempts, which is ridiculous. He's thrown for 9,029 yards and 76 scores.

Why he's here: Yes, it's a quarterback-friendly system, but Falk has obvious control of the offense. His superb touch is most evident on sideline passes, and there are plenty of those built into Washington State's philosophy. Although a real concern for the 22-year-old's future is average velocity, he's excelled without it in college.

Biggest tests in 2017: A Friday night showdown with USC in September is an important landmark. However, the difference between Falk's being good or great will be seen in November, when the Cougs host Stanford before traveling to Utah and Washington. The Pac-12 North Division title will likely be at stake.

7. Deondre Francois, Florida State

By the numbers: After taking a redshirt in 2015, Deondre Francois put together an impressive first season. The mobile pocket-passer hit 58.8 percent of his 400 throws, guiding Florida State to a 10-3 record while tallying 3,350 yards and 20 touchdowns.

Why he's here: Francois must improve when facing pressure, but he's a promising talent in every other aspect of the position. Deep passes? Got it. Small-window sideline throws? No worries. Stand in the pocket and take a hit? Maybe even too willing. The 6'2", 205-pounder is a spectacularly tough and accurate quarterback.

Biggest tests in 2017: The offensive line could be shaky once again, so it's not an ideal time for an unrelenting schedule. Alabama, Miami and North Carolina State should boast three of the nation's best front sevens, and they're all on the slate in September. Throw in matchups with Wake Forest, Boston College, Clemson and Florida, and Francois must be ready to absorb huge hits nearly every week.

6. Josh Rosen, UCLA

By the numbers: As a freshman in 2015, Josh Rosen backed up the hype with 3,669 yards and 23 touchdowns. However, an injury limited him to six games last season. He mustered 1,915 yards and 10 scores to five interceptions during those appearances.

Why he's here: From a prospect perspective, he would be ranked even higher. Rosen isn't a finished product, but he's a refined player. Scouts are already fawning over his footwork, base and throwing motion, and deservedly so.

Biggest tests in 2017: Not only will Rosen take on USC and Washington, but he's also learning yet another offensive system. Jedd Fisch should have a positive effect on the 20-year-old's development, but this is still his third coordinator in three years at UCLA.

5. Sam Darnold, USC

By the numbers: Sam Darnold took over as USC's starter in a loss to Utah. Then he helped the Trojans rattle off nine consecutive wins. The signal-caller ended his freshman campaign with 3,086 yards, 31 touchdowns and nine interceptions.

Why he's here: Perhaps it's a surprise to see Darnold isn't higher on the list, but the redshirt sophomore needs to clean up a few pieces of his game. He can be jumpy in the pocket and hesitant to make downfield throws because of inconsistent footwork. But the 20-year-old will pick apart any blitz, and his arm talent should atone for most concerns about his atypical throwing motion.

Biggest tests in 2017: Expectations can hardly be higher for Darnold. Will that external pressure lead to forced throws and mistakes? He will need to overcome that mental battle and handle the experienced defenses of Stanford, Washington State and Colorado.

4. Logan Woodside, Toledo

By the numbers: Logan Woodside waited patiently for his second opportunity to start and took full advantage of it. He shattered school records with 4,129 yards and 45 touchdowns, recording a 69.1 completion mark and tossing just nine interceptions.

Why he's here: Between his snappy release, velocity and touch, Woodside has the fundamentals to make his production look even better. His stature—6'2", 201 pounds—will affect NFL assessments, but it's impossible to argue with his contributions at Toledo.

Biggest tests in 2017: The final nonconference game of September is a road trip to Miami, where an aggressive defense awaits the Rockets. Once they enter MAC action, Woodside must navigate Northern Illinois (led by star corner Shawun Lurry) and Western Michigan.

3. Mason Rudolph, Oklahoma State

By the numbers: Following a year in which he collected 3,770 yards and 21 touchdowns, Mason Rudolph lifted his season totals to 4,091 and 28, respectively. The signal-caller also finished the 2016 campaign with a 63.4 completion percentage.

Why he's here: Similar to Falk, Rudolph, 21, has absolute control of the offense. He's adept at making pre-snap reads and is comfortable going through a progression. Velocity is a minor concern, but he is accurate on short and deep routes from sideline to sideline—and his anticipation helps mitigate an average-ish arm.

Biggest tests in 2017: While the return of the Big 12 Championship Game gives Oklahoma State a slightly larger margin for error, the four-game stretch that includes Baylor, Texas, West Virginia and Oklahoma should determine whether the Pokes reach the title matchup.

2. Mike White, Western Kentucky

By the numbers: Brandon Doughty left a significant void on Western Kentucky's offense, but Mike White filled it admirably. The South Florida transfer connected on 67.3 percent of his 416 passes, tallying 4,363 yards and 37 touchdowns to only seven interceptions.

Why he's here: White terrorized secondaries downfield in 2016. Per Pro Football Focus, his 1,762 deep passing yards leads all returning quarterbacks. Although the next step in his development is attacking the middle of the field with confidence, Jeff Brohm's system didn't require that of him often. That may change under new head coach Mike Sanford.

Biggest tests in 2017: The ability to accurately throw deep passes doesn't just disappear with a receiver, but not having Taywan Taylor or Nicholas Norris will be a challenge. Road trips to Old Dominion and Vanderbilt pose the biggest team threats.

1. Baker Mayfield, Oklahoma

By the numbers: Baker Mayfield has been a Heisman Trophy finalist in both seasons as Oklahoma's starter. He threw for 3,700 yards and 36 touchdowns in 2015, and he then led the nation with a 70.9 completion percentage in 2016 and tossed 40 scores.

Why he's here: Pressure him at your own risk. According to Pro Football Focus, Mayfield leads all returning quarterbacks with 20 touchdowns against the blitz. Below-average height for a quarterback is the major knock on the 22-year-old, but the 6'1", 218-pounder has a respectable arm and is dangerous both in rhythm and as a scrambler.

Biggest tests in 2017: Mayfield seems like a quarterback who can elevate his offense, but that hypothesis will be thoroughly examined while the Sooners replace Dede Westbrook, Samaje Perine and Joe Mixon. Oklahoma also travels to Ohio State, which should replace an NFL-caliber secondary with yet another one—again.

Stats from cfbstats.com or B/R research. Follow Bleacher Report CFB Writer David Kenyon on Twitter @Kenyon19_BR.