I've had a theory for quite a while on college quarterbacks heading into the NFL...and it doesn't look good for Marcus Mariota or Jameis Winston.
Here is a list of the quarterbacks that faced each other in the national championship game over the past 15 years...
Jameis Winston
Nick Marshall
AJ McCarron x2
Everett Golson
Zach Mettenberger
Darron Thomas
Cam Newton
Colt McCoy
Greg McElroy
Tim Tebow
Sam Bradford
Matt Flynn
Todd Boeckmann
Chris Leak
Troy Smith
Vince Young
Matt Leinart x2
Jason White x2
Matt Mauck
Ken Dorsey x2
Craig Krenzel
Eric Crouch
Chris Weinke x2
Josh Heupel
Michael Vick
Certainly not an impressive list by any means as only Vick, Weinke, Leinart, Young, Bradford, Tebow, McCoy, and Newton have even been a starter in the NFL at any time..and recently Mettenberger but who knows what he will be. Out of the 5 guys that have made multiple appearances in the National Championship game nobody is active in the NFL.
My QB theory on this one is that if you are a high level, highly ranked team in CFB the quarterback gets blown WAY out of proportion. Take Winston for example...he has one of the best offensive lines, two great running backs, and top level wide receivers. He's still struggling this year with interceptions. It's the reason why Tim Tebow and Chris Weinke and Vince Young struggled so much when they got to the NFL. When you don't have the absolute best talent on the field with the best coaching staff week in and week out, you actually have to rely on your brains and reactions...which is just not something that is developed at high level schools.
So to further this theory, I looked at the quarterbacks in the NFL right now and when you take a look at their college careers you would be hard pressed to support your favorite team taking Winston or Mariota or any other QB on a major CFB team.
Peyton Manning is really the ONLY example in the NFL right now that was a superstar QB in college and transferred that at the next level...but how many guys have a father that was in the NFl and a brother that is in the NFL? You can throw Andrew Luck in that same category, but he couldn't lead Stanford to anything higher than a #4 ranking...never really sniffing the national championship.
So here's the list of NFL quarterbacks other than Manning/Luck and their college...
Brady - Michigan, mostly a backup
Tannehill - Texas A&M, played receiver
Orton - Purdue
Geno Smith - West Virginia
Dalton - TCU
Flacco - Delaware
Roethlisberger - Miami U (not THE U)
Hoyer - Michigan State
Fitzpatrick - Harvard
Mettenberger - LSU...mentioned earlier
Bortles - Central Florida
Alex Smith - Utah
Rivers - NC State
Carr - Fresno State
Romo - Eastern Illinois
Eli Manning - Ole Miss
Sanchez - USC (1 decent year, mostly backup)
Colt McCoy - Texas, Mentioned earlier
Griffin - Baylor
Rodgers - California
Stafford - Georgia
Cutler - Vanderbilt
Bridgewater - Louisville
Ryan - Boston College
Brees - Purdue
McCown - SMU/Sam Houston
Newton - Auburn, mentioned earlier
Kaepernick - Nevada
Wilson - Wisconsin/NC State
Palmer - USC, possibly the most successful, 1 good college year
Bradford - Oklahoma, mentioned earlier, could be done
Hill - Maryland
So basically, if you're an NFL team and you draft a QB that went to a college powerhouse than contended for the National Championship, your best case scenario is Cam Newton, Carson Palmer, Sam Bradford.