An interesting class is hard to grade

If this year's crop of defensive backs is broken into two parts, the natural place to start is safety and cornerback. But let's take it one step farther, examining one of the dilemmas NFL scouts often grapple with.

It's the body-of-work meter.

Mainly, personnel evaluators like the idea of grading a player over a longer starting career, because it gives them more film to study, more information to assess. A riskier and more difficult projection is evaluating a player with a shorter college career, or a shorter stint as a starter at a top school.

This year's top defensive backs offer a significant contrast in that regard.

Louisiana State safety LaRon Landry and Michigan cornerback Leon Hall, both first-round talents, top the ironman charts. Landry played a whopping 52 collegiate games (48 starts) over four seasons, while Hall has 50 games and 37 starts on his résumé.

At the opposite end of the defensive back spectrum are Florida safety Reggie Nelson and Texas cornerback Aaron Ross, both of whom are first-round worthy. Consider that Nelson played in 25 games (18 starts) over two seasons with the Gators (he was previously in junior college for two years), while Ross was a three-year backup until last season.

The dilemma for scouts is how to balance their more complete projection of players like Landry and Hall against the potential of players with less starting experience like Nelson and Ross.

Landry (6 feet 1/2 inch, 213 pounds) is considered the cream of the defensive back crop, a player who prides himself as a complete safety, offering a team two important skills in one: the ability to cover down the field and play in the box to support the run.

"You find very few safeties that can do both," Landry said at the NFL Combine in February. "I guess that's why it became a glamour position."

Indeed, this year continues a trend that highlights how safeties have grown in importance to NFL clubs, as Landry, Nelson (5-11 3/8, 198), Texas's Michael Griffin (5-11 3/4, 202), and Miami's Brandon Meriweather (5-10 5/8, 195) all could be selected in the first round. And if Landry is the first DB off the board -- he is projected in the 5-10 range -- it will mark the third time in four years a safety was selected before a cornerback.

As for the cornerbacks, Hall and Pittsburgh's Darrelle Revis (5-11 1/2, 204) are 1-2 on the draft boards of several NFL clubs. The sturdy Revis, who enters the draft after his junior season, started 34 games over the last three seasons and isn't expected to last into the second half of the first round. Texas's Ross (6- 1/2, 193) and Arkansas's Chris Houston (5-9 7/8, 185) also could go in the first round, although the best value at the position might be in the second and third rounds with players like California's Daymeion Hughes (5-10 1/8, 190), Maryland's Josh Wilson (5-9 1/4, 189), Tennessee's Jonathan Wade (5-10, 195), Fresno State's Marcus McCauley (6-0 3/4, 203), and UNLV's Eric Wright (5-10 5/8, 192).

As for New England players, Boston College's Larry Anam (5-11 3/4, 192), New Hampshire's Corey Graham (5-11 7/8, 195), and Maine's Daren Stone (6-3 1/4, 218) will look to hook on with NFL clubs, with Graham having the best chance to be drafted.

Other odds and ends from defensive backs: