NFL Draft 2012: Analyzing BCS Conference QBs Who'll Become Undrafted Free Agents

For as important as the quarterbacks are, and for as much exposure as a college player gets from competing in a BCS conference, becoming an undrafted free agent is still rather common.

Some may have the size, mobility, arm strength but it's clear that not all the tangibles are complete enough to be considered at potential draft pick.

That said, here's a look at some familiar BCS quarterbacks who are likely to become free agents this spring.

Darron Thomas, Oregon

With great size, athleticism and an abundance of success, you would think that Oregon's Darron Thomas is a lock to be drafted.

The man is 6'3", 215 pounds and is mobile as any quarterback in the draft. Not to mention his numbers are unreal.

Combined between 2010 and 2011, Thomas threw for over 5,600 yards, 63 touchdowns to just 16 picks, a combined completion percentage of 61.8 and the Ducks went 24-3 during this span.

So why is he an unlikely pick?

Well, for one, Thomas came out earlier than expected and played in an offense not only loaded with talent around him, but where he didn't have to make NFL-esque reads.

Rarely under center, didn't sit in the pocket and progress his reads while dissecting a defense and scrambled quickly after not finding his No. 1 target. Simple zone blitz schemes will get to him and any man coverage looks will simply spy him with a nickel/dime back.

Therefore, unless Thomas develops into a pass-first quarterback who can become aware of the rush, it wouldn't be surprising to see him get moved to wide receiver.

Jordan Jefferson, LSU

Much like Darron Thomas, LSU's Jordan Jefferson has great size (6'4", 220 pounds) and solid mobility.

Unfortunately, that's about all you can say about Jefferson's tangibles. He's not impressively accurate, is turnover-prone and tries to do too much himself.

Now, Jefferson did have a sound 2009 season where he threw for 2,166 yards, had 17 touchdowns to just seven picks and a 61.5 completion percentage. But, all was for naught in regards to his future.

In 2010, Jefferson compiled just over 1,400 yards to seven touchdowns and 10 interceptions while declining with a 56.5 completion percentage. He also used his legs more and ran for 450 yards that also included seven touchdowns.

So if anything, it's inconsistency at the helm and then after the way his 2011 campaign began, his intangibles will be questioned. Plus, once Jefferson was cleared to play this past season, he only attempted more than 20 passes one time.

In the pass-happy NFL, his legs will get extremely tired from scrambling and then turnovers will occur.

John Brantley, Florida

Another guy with good size, Florida's John Brantley comes in around 6'3", 220 pounds and is more accurate than meets the eye.

Brantley's mechanics are also not too bad as he knows how to set up his feet and has decent setup from under center. The downside however, is that Brantley's stats really put a damper on what he's physically capable of.

Once Tim Tebow left for the NFL, Brantley took over in 2010 and threw just nine touchdowns to 10 picks. His completion percentage was 60.8 and Brantley also hit over 2,000 yards but nothing overly impressive.

So with 2011 expecting to be better, it was, but the stride wasn't indicative of a quarterback who has really developed and improved.

There, Brantley threw just 11 touchdowns to seven picks, 2,044 yards and a 60.0 completion percentage. Not to mention he attempted 89 less throws and missed two games due to injury.

The concern here is not only durability after an injury last season, but simply scanning through his progressions while in the pocket. He can get a little impatient because of blitzers and roll down safeties and defensive ends dropping underneath the intermediate routes can faze him.

Dan Persa, Northwestern

He may appear a bit undersized at 6', 210 pounds but Dan Persa, if anything, has accuracy going for him.

Taking over the full-time starting role in 2010, Persa had thrown for 2,581 yards, 15 touchdowns to just four picks and had a 73.5 completion percentage.

Northwestern was 7-3 when he got injured and lost the final three games.

Coming back for 2011, Persa missed some early games because of the injury and returned for the Big Ten opener against the Illinois Illini.

Needless to say, Persa didn't miss a beat and he closed out the year with almost 2,400 yards, 17 touchdowns to just seven picks and a 73.4 completion percentage.

There's no doubt that Persa does need to work on his arm strength and have a little more patience in the pocket. Of those mentioned on this list however, he's arguably the best player because of his accuracy, ability to buy time and then only scramble when needed.

He also has durability concerns having to miss six straight games (final three of 2010, first three of 2011) but if there's one guy who can scan defenses and call the proper audibles, it's Dan Persa.

John Rozum on Twitter.