NFL Combine 2012: Potential Round 1 Defensive Prospects with the Most to Prove

The 2012 NFL draft certainly has prospects with not much to prove considering their complete college-playing accolades. We expect first-rounders such as Andrew Luck, Robert Griffin III and Trent Richardson to impress.

There are however, other first-round prospects that still have a lot to prove because of inexperience or a recent lack or production, or a combo of the two. That said, here are some potential Round 1 defenders who must impress at the combine.

Alfonzo Dennard: CB, Nebraska

Playing opposite of Prince Amukamara at Nebraska, Alfonzo Dennard was challenged quite often by opposing quarterbacks. Then, after Prince left for the pros, Dennard was the heir that took over and locked down in 2011.

Dennard's physical play, field awareness and willingness to help with edge run support made him a top-notch defensive back prospect. Unfortunately, he had a disappointing performance during the Senior Bowl week and was exploited by quicker receivers as well as those who were fluid route-runners.

At the combine, Dennard must prove he can play a few steps off the line then explode up into a late press-coverage look. In addition, he must learn to bail at the snap while staying in tight coverage.

Although jamming receivers at the line is his best asset, you can't take that risk on every snap. NFL receivers will swim or fake-step past him en route to making big plays.

Michael Brockers: DT, LSU

The sole concern here is youth and inexperience. There's no doubt the LSU's Michael Brockers has the potential to be a first-rounder, but he's only a redshirt sophomore and has just one season of legitimately contributing as a starter under his belt.

Now of course, it's tough for any youngster to make noise at LSU, but one more season at the college level would only solidify Brockers' potential even more. Last season he may have only recorded two sacks, but also had 54 tackles (10 for loss).

What scouts don't get to evaluate is his consistency on an annual basis, since he's leaving early. In addition, Brockers is also missing out on an extra year to develop conditioning and technique.

Those attributes are arguably the two that go hand-in-hand more than anything, because players who rarely get tired never lose technique. It's not that Brockers can't improve there, but older players have the advantage over him.

Whitney Mercilus: DE, Illinois

Much like with Brockers, Illinois' Whitney Mercilus must prove his dominance on an annual basis. Mercilus is the older of the two and received playing time in 2009 and 2010.

Those campaigns, however, could not match Mercilus' breakout season in 2011 even if you combine them.

Last year, Mercilus recorded 16 sacks, forced nine fumbles and made 57 total tackles. Can you imagine that kind of production two years in a row? Had Mercilus done that he'd easily be a Top 15 pick at worst.

As for the combine, he must learn to control his aggressiveness by not taking himself out of a play. Also, Mercilus still needs to develop more as a backside run-stopper, because getting off blocks then reacting to a cutback can be the difference between allowing a one-yard gain or a first down.

Simply put, Mercilus needs to improve his reactionary skills while utilizing the hands to put himself in position to make plays.

John Rozum on Twitter.