Dan Pompei

These are the most volatile days for the draft stock market. In the wake of the scouting combine, the value of some players is shooting up while the value of others is spiraling down.

Here is a look at ten players whose stock was significantly affected by their combine performances. Times for 40-yard dashes are unofficial.

Jahvid Best, California RB — stock up
He might have moved from the bottom of round 2/top of round 3 to the top of round 2 with a very nice workout, including a 4.35 40. He’s a love him or hate him type of player. Some think he’s no better than a No. 2 back and kick returner. But the scouts who think he’s more than that like him more than ever now.

LeGarrette Blount, Oregon RB — stock down
After not playing most of the season because of a suspension, Blount had an opportunity to make a strong impression at the combine but failed. His 40 time of 4.72 was alarming, and he didn't look like a natural pass catcher.

Navorro Bowman, Penn State LB — stock down
It was assumed that Bowman would run better than in the 4.7s. Some teams will struggle with the dilemma of taking a linebacker who runs a 4.7 in the first round, so Bowman could have dropped into round 2, maybe behind Missouri’s Sean Weatherspoon.

Bruce Campbell, Maryland OT — stock up
If you judged Campbell on his game tape, you’d say he’s a mid-round pick. But if you judged him on how athletic he looked at the Combine, you’d say he’s a sure first-rounder. He helped his stock just by showing up for the weigh-in wearing nothing but a pair of shorts—at 6-6, 314 pounds, he has the prototype body to play tackle in the NFL. He drew more attention with a 4.85 40 (as if a 40-yard dash matters to offensive linemen), and an excellent overall workout.

Perrish Cox, Oklahoma State CB — stock down

Slideshow   2010 NFL Draft: Top 15 QBs Evan Silva ranks the top 15 quarterbacks who will be available in this year's NFL draft. Rotoworld.com

Cox needed a strong Combine, given that he was suspended for his college team’s bowl game. But Cox was slower than expected, running a 4.55 40. One front-office man said Cox was not impressive in interviews, either.

Brandon Graham, Michigan DE/OLB — stock up
Building on the momentum he gained at the Senior Bowl, Graham had an excellent workout with a 4.67 40 and 31 bench presses at 225 pounds. He could have helped himself even more by proving he can drop and cover in linebacker drills, but he injured his hamstring and pulled out early.

Joe Haden, Florida CB — stock down
Haden was expected to be a top-15 pick, and it was assumed he would run a 4.4 40. But he ran a 4.58, and he didn’t look so hot in his agility drills either. As a result, a good chance exists he will drop out of the first half of the first round.

Taylor Mays, Southern Cal S — stock up
One personnel director jokingly said Mays won “The Combine Award.". At 6-3, 230, Mays ran the 40 in the low 4.4s. His combination of size and speed is tantalizing, even if the game tape is less so. It seems certain Mays will be gone by the mid first round after his workout.

Jason Pierre-Paul, South Florida DE — stock up
He is the kind of player who benefits most from the combine — a spectacular athlete who is a bit raw. Pierre Paul might have moved into the top ten of the draft, as he generated a buzz among scouts with a phenomenal workout, including a 4.67 40. What’s more, he demonstrated position versatility.

Damian Williams, Southern Cal WR — stock down
It’s bad enough for any wide receiver to run a 4.6 40 at the Combine, but it’s a killer for a receiver from Southern Cal. There is a stigma about USC receivers not being fast enough, and it could impact where Williams is drafted. He might have dropped from the high second round to the low second round.