Speed thrills at combine

The NFL combine has come a long way.

I first started covering it in 1990. A handful of reporters sat near an elevator intercepting players. Although we weren't allowed to see the workouts, we could get interviews and start previewing the draft.

Now, it's one of the big events on the NFL calendar. It's televised on the NFL Network. The NFL distributed 750 credentials. All but 48 of the non-kickers ran 40-yard dashes, easing the load for scouts over the next two months as they try to fill out their reports.

For the first time, the NFL let 250 fans attend the Sunday session. That was a success. Expect more fans to see more in future years. The league is even talking about having prospects compete against each other in 40s and other drills.

In the past, those who ran the combine tried their best to prevent 40 times and other drill results from getting outside the scouting circles. Now, they are published online within seconds. That's progress.

So what did we learn from the 2012 combine?

1. Receivers are bigger and faster than expected: The receivers who ran during the combine clocked an average 40 time of 4.51. Eight had sub-4.4 40s. The big winner was Stephen Hill of Georgia Tech. At 6-foot-4 and 215 pounds, Hill may have pushed his second-round grade into a first-round spot by clocking an official 4.36 40, although others had him at 4.3 and 4.31. Michael Floyd of Notre Dame solidified his top-15 status by running a 4.47 40 and checking in at 6-2 5/8 and 220 pounds. Chris Givens of Wake Forest wasn't the tallest receiver at 5-11, but he was impressive in running 4.41. Both groups of receivers were consistent catching the football. Still to be determined is a 40 time for the best receiver, Justin Blackmon of Oklahoma State. He didn't run because of a tight hamstring but he did the drills. Though he didn't wow anyone in the drills, expect him to put on a show at his pro day.

2. The race for the No. 3 QB slot: Four of the top quarterback prospects didn't throw: Andrew Luck, Robert Griffin III, Ryan Tannehill and Brock Osweiler. Kirk Cousins of Michigan State was the best thrower over the weekend. At the very least, he improved his stock into the second round and could make a push for the first. Brandon Weeden didn't have a great weekend throwing and lost ground to the other top quarterbacks. Tannehill, Osweiler and Cousins will be the options for the teams that don't get Luck or Griffin. One of the best throwers was Russell Wilson of Wisconsin, second only to Cousins. But he measured at 5-10 5/8.

3. RB class filled with sleepers: Trent Richardson of Alabama didn't work out because of recent knee surgery, but he's the best back in the draft. The surprise was the speed of the other backs. David Wilson of Virginia Tech and Lamar Miller of Miami (Fla.) both ran in the low 4.4 range, which may make them low first-rounders. LaMichael James of Oregon established himself as a Darren Sproles-type option by getting an official 4.45, but others clocked him at 4.37. Chris Polk's official number of 4.57 may not have been impressive, but he ran well. Polk is one of the better inside runners of the group and will draw second-round consideration.

4. Those big guys can run: Defenses are looking for speed, so the scouts had to be impressed with this class of defensive linemen. Thirty-one of the 59 linemen ran sub 5-second 40s. Most impressive was Nick Perry, a defensive end from Southern Cal. He officially received a 4.64 40, but he was clocked at 4.5, amazing for a 271-pound defensive end. Bruce Irvin of West Virginia opened a few eyes with a 4.5 40. Perhaps the most remarkable workout was by Dontari Poe, a defensive tackle out of Memphis. Weighing 346 pounds, he ran an official 40 of 4.98, although some had him under 4.9. He also recorded 44 reps in the bench press (225 pounds). This is a special group of athletes along the defensive line.

5. Some disappointments: After Matt Kalil of USC (who stands out as the best tackle in the draft) and David DeCastro of Stanford (the best guard), no one wows you. Michael Adams of Ohio State has the body to be a top tackle, but he benched only 19 reps, making his strength a question mark. Cordy Glenn of Georgia is an impressive athlete, but there is no guarantee he will be a top tackle. The offensive line group is deep, but it's not great except for the top two. Times for the defensive backs were a little disappointing. They averaged 4.54, 0.03 slower than the receivers. Morris Claiborne of LSU and Dre Kirkpatrick of Alabama stood out as the best two cornerbacks even though their times weren't great at 4.5. Mark Barron of Alabama, the top safety in the draft, didn't work out because of a hip injury. As has been the case the past few years, the safety position looks thin. Still, there is decent size at cornerback, which should help teams that are looking for man-to-man corners. The tight end position also was a disappointment. No one really stood out there.

John Clayton, a recipient of the Pro Football Hall of Fame's McCann Award for distinguished reporting, is a senior writer for ESPN.com. Follow Clayton on Twitter