The Atlanta Falcons' situation at cornerback will remain very fluid from now up until draft day, and the reason for this is Brent Grimes. Due for a big pay day in 2012, Grimes will likely leave the Falcons for more money unless the front office decides to slap the franchise tag on him, which is definitely a possibility. Until we know more about Grimes' status I think it's prudent to examine the CB position in a manor that assumes he'll be gone, and Atlanta will be looking for a future starter at the position.
There's an outside chance someone line Janoris Jenkins could fall, but it's far more likely that Jamell Fleming, the 5'11" CB out of Oklahoma will be a player to really watch as the combine rolls around. In a lot of ways Fleming reminds me of Devin McCourty coming out of Rutgers; not overly physical, and definitely lacking some of the tools you want but he was a smart cornerback with excellent lateral speed who could overcome a lot of his physical weaknesses.
Despite missing two games in 2011 due to academic ineligibility Fleming was able to put together a fairly impressive resume for the Sooners: 50 tackles, 2 INT and 2 FF. There's no doubting his totals fell a little from 2010, but overall he put together another solid season.
Currently the National Football Post are grading Fleming at 6.8/10, which puts him in the 'future starter' range. They go on to say:
He's a balanced, coordinated kid who keeps his feet under him when changing directions and can turn and run. Doesn't give up much separation, knows how to make plays on the football and if he can improve as a tackler looks like a guy who warrants a starting job in the NFL down the line.
It's always a risk taking players who need to improve a vital area of their game like tackling, and hope you can hone it at the next level. This is exacerbated when you consider that Fleming would be expected to be the #2 CB for Atlanta, and as such be responsible for the NFL's larger possession receivers. However, he is a play maker with a knack for making an impact, and as such he could be the most attainable CB for the Falcons in the second round.