2013 NFL Draft: Under-the-radar underclassmen that could be sleepers

Stefphon Jefferson finished second in the nation in rushing yards in 2012. (Tom Smedes/Icon SMI)

Upwards of 70 underclassmen have declared for the 2013 NFL Draft. As always, there's a big range of available talent, from front-of-the-line guys like Jarvis Jones and Damontre Moore to a host of lesser-known players.

There figure to be a few hidden gems in the second group -- every draft uncovers at least a couple diamonds in the rough.

So, which of this year's early entrants could turn into stars down the road? Here's a look at five underclassmen who may fly under the radar ... only to become very productive NFL players:

FULL LIST OF ALL EARLY ENTRANTS

• Stefphon Jefferson, RB, Nevada: The race is on for teams to find the next Alfred Morris, so what better candidate than a player who had 375 rushing attempts, more than 1,800 yards and 24 touchdowns this season while running out of the pistol formation that's swept the NFL?

Jefferson has good size -- he's listed at 5-foot-11, 210 pounds, which is what Montee Ball also stands at -- and does a nice job squeezing up through holes on the offensive line. He did a lot of his running straight downfield, though he also had success on those stretch plays that are such a staple of the pistol and zone-read offenses.

He won't scare opposing defenses out of the backfield much (7.7 yards per catch on 22 receptions in 2012), and there are more than a couple pieces of tape showing him whiffing on blitz pickups.

Because Jefferson does not really leap off the screen (he looks fairly stiff at times when he's running), it's safe to assume he will slip into the mid-to-late rounds. Right into Alfred Morris territory.

• Corey Lemonier, DE/OLB, Auburn: Lemonier had an impressive 2011 (9.5 sacks) and started 2012 strong, too, with five sacks in his first four games. He had just a half-sack the rest of the season, though, and was even yanked from the Tigers' starting lineup for the season finale against Alabama.

The question will be: Do NFL teams focus more on his obvious potential or that drop-off?

If they choose the former, they might be happy with what they find. Lemonier played defensive end for Auburn -- both with a hand in the dirt and standing up -- so he could stay there in a 4-3 or slide to a pass-rushing outside linebacker spot in a 3-4. And the ability to get to the quarterback remains, thanks to Lemonier's quick jump off the line.

This could be a big draft for the DE/OLB types, with Damontre Moore, Bjoern Werner, Barkevious Mingo, Dion Jordan, Alex Okafor and others potentially going in Round 1. Lemonier figures to be more of a Day 2 prospect, but his numbers might not be that far off the elite talents.

• Josh Boyce, WR, TCU: The 5-11 Boyce turned in a consistently productive three years with the Horned Frogs. He caught 61 and 66 passes, respectively, in his sophomore and junior campaigns, while averaging nearly 15 yards per catch.

That ability to stretch the field will intrigue NFL teams -- Boyce had catches of 93 and 94 yards during his TCU career, plus a 61-yarder in a December bowl loss to Michigan State. Boyce also has experience at numerous receiver spots. He played mostly on the outside at TCU, but he did line up in the slot on occasion and may be a more lethal prospect there down the road.

It's hard to get a read on where exactly Boyce will fall, given the number of WR prospects that could slip into Days 2 and 3 of the draft. His history and upside should get him a mid-round opportunity.

•Menelik Watson, OT, Florida State: Expect to hear a lot about Watson's story over the next few months. A native of Manchester, England, Watson took a roundabout path to a spot on Marist College's basketball team. He then switched to football in 2011 and played in junior college, before moving on to Florida State for one season.

As you might expect given that background, Watson is a very raw prospect. But at 6-5 and an athletic 320 pounds, he's the type of developmental pick that more than one NFL team would love to have, even though Watson already is 25 years old.

He looked absolutely dominant, from time to time, during Florida State's 2012 season. Given another year to improve at the collegiate level, he might have been a Round 1 or Round 2 prospect. Watson will slip a little lower than that in April, but he could turn into a steal.

•Levine Toilolo, TE, Stanford: Toilolo's college teammate, Zach Ertz, will be one of the big-money tight ends this year -- Ertz could follow in the footsteps of Coby Fleener, who was picked No. 34 overall in 2012 by the Colts. Toilolo ought to be the third Stanford TE taken the past two drafts, likely somewhere late in Day 2 or early in Day 3.

The production is not there for Toilolo, like it is for Ertz -- the former caught just 24 balls in 2012, compared to 69 by his teammate. Toilolo also had a very disappointing day in Stanford's loss to Notre Dame, as he finished without a catch and was pushed around a bit on the line; he also failed to haul in any receptions in the Rose Bowl vs. Wisconsin.