So what the heck is Percy Harvin?

"I don't know what he is, honestly," Vikings receivers coach George Stewart said. "I don't know if he's a receiver. I don't know if he's a running back. I don't know if he's a returner. But I do know this: He's a darn good football player."

In a league that's been around 92 years, Harvin is the rare talent that can't be defined by comparisons to his peers or the thousands who have gone before him. He has the hands of a receiver, the natural instincts and power of a running back, the strength of a linebacker and a cool nickname that sums it all up nicely for this 5-11, 184-pounder.

"AP [Adrian Peterson] started calling me 'Mighty Mouse' my rookie year, when we played the Ravens," said Harvin, the NFL's Offensive Rookie of the Year in 2009. "It was that block I put on Ray Lewis. I got up and started talking [to Lewis] a little bit, and guys were impressed. I think they thought I was supposed to be scared because it was Ray Lewis."

Seems, um, logical. But Harvin isn't a typical star receiver. For gosh sakes, he earned a game ball this season for ... blocking!?

"On Ray, it was a block that sealed the corner and let AP run right behind me," Harvin said. "Just a chip block. Ray and [Terrell] Suggs were coming off the edge and I had to hit one of them. So I chose Ray. We kind of had a little noise."

That was when Stewart knew he was working with an unusual receiver.

"All week, we kept saying, 'Percy, you have to go and get Ray Lewis on this play,' " Stewart said. "Then he went and stoned Ray Lewis. But that's Percy. He's just a tenacious football player."

Lewis got even, of course.

"The following play is when Ray tackled me and my helmet came off," Harvin said. "But I jumped up like he was any other player and got in his face. That's when I think I won the team over."

Needed more than ever

The Vikings improved to 6-0 en route to the NFC Championship Game with that 33-31 victory over the Ravens two years ago. Harvin, the 22nd overall draft pick that year, was on his way to a team-record 2,081 combined yards, breaking a mark set by Herschel Walker in 1990.

Boy, how things have changed. Harvin is still setting team records because of his unique combination of skills. But the Vikings as a team are 15-23 since then. At 2-8, they need to beat the Falcons (6-4) in Atlanta on Sunday to avoid tying the worst start in franchise history.

Peterson won't play because of a high left ankle sprain. The Vikings will start Toby Gerhart and work in Lorenzo Booker.

They won't need to add a third running back. Not when Harvin has proven to be the second-best running back on the roster behind Peterson.

Harvin already has 28 carries for 224 yards (8.0 average) and a touchdown. That tops Gerhart by four carries, 118 yards and one touchdown.

"The Vikings are doing some unique things when they line Percy up in the backfield and ask him to run the same plays that a running back would run," Falcons coach Mike Smith said. "I've not faced that in my time in the NFL. I haven't had to prepare for anything like that until this week."

Scott Studwell, Vikings director of college scouting, said comparisons to Panthers receiver Steve Smith kept coming up when the Vikings were discussing Harvin before the 2009 draft. Smith became an elite receiver despite being only 5-9 and 185 pounds.

In 10-plus seasons, Smith also has 51 carries for 327 yards (6.4-yard average) and two touchdowns. Harvin already has surpassed those rushing totals with 61 carries for 466 yards (7.6-yard average) and two TDs in two-plus seasons.

Vikings offensive coordinator Bill Musgrave said Harvin reminds him of ex-Viking Ahmad Rashad, who was a running back at Oregon, and Irving Fryar, the longtime Patriots receiver who was a running back at Nebraska. But even Fryar had only 44 carries in 17 NFL seasons.

"It's kind of like Percy is that one-of-a-kind deal at receiver," Vikings receiver Michael Jenkins said. "It's like he's a Dave Meggett, but we all know Meggett was a running back [for the Giants]. So I don't know what to tell you."

Pound for pound the strongest

Harvin was a three-sport star at Landstown High School in Virginia Beach, Va. He ran a 4.32 40-yard dash as a freshman. He won five gold medals at the state track meet his junior year. He helped the basketball team to a state runner-up finish.

As a junior running back, he capped a 14-0 season with 476 all-purpose yards in the state title game.

"Then, before my senior year, Christopher Beatty, my high school coach who's now [an assistant] at Vanderbilt, came to me and said, 'I think you got a future as a slot receiver,' " Harvin said. "He said, 'You'll always have your running back skills, but you can make a future for yourself in the slot.' "

Beatty knows his football. Harvin went on to win two BCS national championships as a slot receiver/running back at Florida.

Now with the Vikings, he has set numerous team rushing records for a receiver. He moved past Anthony Carter in career yards and attempts this season. He has also set the single-season marks for attempts and yards. And his 67 yards rushing in the win at Kansas City broke the single-game mark set by Bob Grim 40 years ago.

In 48 seasons without Harvin, the Vikings never had a player score three different ways in multiple seasons. Harvin has done it in back-to-back years after catching his first touchdown pass of the season last week.

In 48 seasons without Harvin, the Vikings never had a player return more than one kickoff for a score. Harvin, 23, has done it four times. He also has a team-record five games with 200 combined yards.

"You really do completely forget that he's a receiver," said Tom Kanavy, Vikings head strength and conditioning coach. "He's absolutely, pound for pound, one of the strongest players on the team. And not just in certain areas, but overall body strength. With his numbers, he ought to be training with the linebackers and maybe the linemen."

Kanavy said Harvin's leg strength is "off the charts" for a receiver. He can squat 400 pounds multiple times with ease and sound technique. He can leg press 600 pounds.

"The only confrontational moments or issues I've ever had with Percy is when I tell him he's got to ease up in the weight room a little bit," Kanavy said. "Maybe there's a recovery period or a day he shouldn't lift, and that's the only time he gets verbally upset with me. He has as much strength and power as any running back that outweighs him by 50 pounds."

More carries ahead

The Vikings public relations staff wanted to know how Harvin's current rushing totals this season compare historically to those of other receivers. So they turned to the Elias Sports Bureau, which says Harvin's 224 yards are tied for ninth place all-time.

But even that list comes with an asterisk because it lists former Cleveland Browns star Eric Metcalf (5-10, 188) five times in the top eight. Although Metcalf was a career triple threat with 541 receptions, 630 carries and 12 return touchdowns, he was drafted as a running back out of Texas (1989) and played that position primarily during his first six seasons.

"I was with the Steelers when Eric was with the Browns," Stewart said. "Eric is the only guy I can think of in the modern history of football that compares to Percy Harvin. Eric might have been a little more shifty, but Percy has more playing strength. And I know Eric at least came in as running back, so ..."

With 174 career catches, Harvin needs three more on Sunday to move past Ted Brown into fourth place for most catches by a Vikings player in his first three seasons. Asked if Peterson's absence means he also will get a few more carries, Harvin smiled and said, "Wink, wink."

"I think there have been running backs who have done things I do," Harvin said. "I guess Marshall Faulk and guys who could split out wide. But as far as a receiver who can play running back like I do? No. So, yeah, I guess I am different."