ESPN NFL

There is a lot of buzz in scouting circles this time of year regarding the potential positions of strength in the upcoming NFL draft. Of course, a few surprise decisions by top underclassmen can render all such speculation useless. With that in mind, here's a look at the 10 underclassmen (ranked by position) who could make or break the top of the 2010 NFL draft board.

Quarterbacks

• Jake Locker, Washington (6-2¼, 222 pounds), Grade: 96
• Sam Bradford, Oklahoma (6-4, 214), Grade: 95
• Jimmy Clausen, Notre Dame (6-2¾, 217), Grade: 94

At this point, we're working under the assumption that Bradford is entering the 2010 draft. The question now is how many legitimate first-round prospects will be competing with Bradford to be the top quarterback off the board. Locker and Clausen are the underclassmen to monitor. Locker has the best physical tools of the bunch, but he might be better served to spend another year under the tutelage of coach Steve Sarkisian, who had a hand in developing Carson Palmer (Bengals), Matt Leinart (Cardinals), Matt Cassel (Chiefs) and Mark Sanchez (Jets) during his days as an assistant at USC. While not as talented as Locker, Clausen has a good enough combination of size, accuracy and arm strength to develop into a starter in the NFL one day. Clausen also benefits from playing in a pro-style scheme under Charlie Weis at Notre Dame.

Teams in the market for a young signal-caller to build around have to be hoping for an underclassman revolt. Let's face it, the senior class is not strong at this position and even those teams that are high on seniors Tim Tebow (Florida) and Colt McCoy (Texas) will be rooting for the top underclassmen to join the mix in order to generate some depth at the quarterback spot.

For a look at the rest of the underclassmen that can impact the top of the draft, this weekend's can't-miss matchups, a small-school spotlight and Scouts Inc.'s updated top 32, become an ESPN Insider.