Tampa Bay rookie Gaines Adams, taken fourth, could eventually be one of league's leading pass rushers. For now, he's a backup defensive end.

On the flip side, there is Minnesota's Adrian Peterson, the first-year running back who not only leads the league in rushing with 607 yards, but last Sunday against the Bears rolled up 361 all-purpose yards — third most in league history.

With the benefit of hindsight, would any of the teams that passed on Peterson — the Raiders, Lions, Browns, Buccaneers, Cardinals or Redskins — do so given a second chance?

The Vikings, who took him with the seventh pick, are sure glad they did.

Here's a look at 20 of the top rookie performers so far this season (with their overall draft slot), based not on their potential but solely on what they have done in their first six games:

1. Adrian Peterson, RB, Minnesota (No. 7) — Peterson is looking to become the first rookie to lead the league in rushing since Edgerrin James in 1999. He set a franchise record with 224 yards rushing against the Bears.

2. Tony Ugoh, LT, Indianapolis (42) — The Colts' line has done a beautiful job of protecting Peyton Manning, who has been sacked just three times this season. Remember when people thought there would be a big drop-off at left tackle when Tarik Glenn retired?

3. Patrick Willis, LB, San Francisco (11) — The 49ers don't have a lot of reasons to smile, but Willis is one. He already has 50 tackles, ranking him fifth in the league, and has drawn a lot of praise from his position coach. You might remember him: Mike Singletary.

4. Amobi Okoye, DT, Houston (10) — Okoye was the league's defensive rookie of the month in September, collecting four sacks, four quarterback pressures, and forcing a fumble.

5. Trent Edwards, QB, Buffalo (92) — Even though J.P. Losman has returned to practice after suffering a sprained knee, the Bills are sticking with Edwards as their starter. That says something about the Stanford rookie, who has made his share of mistakes yet has a 69.6 percent completion rate.

6. Marshawn Lynch, RB, Buffalo (12) — Lynch has stepped in ably for Willis McGahee, averaging 74.6 yards per game. That's second best among NFL rookies to Peterson's 121.4.

7. Jon Beason, LB, Carolina (25) — Since filling in for the injured Dan Morgan at middle linebacker two weeks ago, Beason has taken over the team lead in tackles and has looked nothing like a rookie. Not coincidentally, the Panthers have won two straight.

8. Dwayne Bowe, WR, Kansas City (23) — Finally, the Chiefs have a promising young wide receiver. Bowe, from Louisiana State, leads all rookies with 26 catches, 415 yards receiving and three receiving touchdowns.

9. Aaron Ross, CB, New York Giants (20) — Earlier this month, Ross made up for a previous benching — he broke an unspecified team rule — in a big way. He had two interceptions against the Jets, returning one for a touchdown.

10. Joe Thomas, LT, Cleveland (3) — It appears Thomas is as advertised: a dominating tackle Cleveland can rebuild around. The Browns have no regrets about taking him so high, nor should they. Barring injury, he'll start for many years.

11. Darrelle Revis, CB, New York Jets (14) — Revis did a respectable job against two of the league's best receivers: Randy Moss and Plaxico Burress. Buffalo's Lee Evans gave him problems, though.

12. LaRon Landry, S, Washington (6) — Landry and Sean Taylor form one of the NFL's hardest-hitting safety tandems. Scouts are impressed with the rookie's instincts and ability to cover ground quickly.

13. Calvin Johnson, WR, Detroit (2) — Johnson is a spectacular athlete — probably the best in the draft — who's finding his place on a team loaded with good receivers. He has 11 catches for 192 yards and two touchdowns.

14. Brian Robison, DE, Minnesota (102) — This fourth-round pick is starting to look like a steal for the Vikings. He leads the team with three sacks, despite never collecting more than seven in a season at Texas.

15. LaMarr Woodley, LB, Pittsburgh (46) — Woodley isn't starting, but he has two sacks for the league's top-ranked defense. Fellow rookie Lawrence Timmons has shown promise, too, and Willie Parker called Timmons the hardest hitter he's ever faced — albeit in practice.

16. Ben Grubbs, G, Baltimore (29) — Grubbs is the most promising young player on a Ravens offensive line that also includes rookie tackles Jared Gaither and Marshall Yanda. Of those, Grubbs looks like the guy who will be a long-term fixture.

17. Eric Wright, CB, Cleveland (53) — Wright, the former USC player who got in trouble and wound up transferring to Nevada Las Vegas, has been playing pretty well for the Browns. He made his first career interception Sunday, tipping a ball to himself and grabbing it in the end zone.

18. Leon Hall, CB, Cincinnati (18) — Hall is one of the few bright spots on a Cincinnati defense in disarray. The Bengals have allowed a league-high — and franchise-worst — 31.2 points per game.

19. Jamaal Anderson, DE, Atlanta (8) — A sack specialist in college, Anderson has yet to collect one in the NFL. Still, as a hulking run-stopper on a left side, he's better than a lot of people expected.