Reasons abound for the uneasiness with freshmen playing college football. Coaches view countless cases of high school standouts being chewed up and spit out by the bigger and badder athletes they face on the college field. They know the magnitude of the transition.
So how do you explain Adrian Peterson?
A year ago, the Palestine, Texas, prodigy had not even decided for sure to attend Oklahoma. He was keeping an eye on the bowl games but playing basketball and getting ready for track.
It stretches the imagination to think he could have envisioned playing for the national championship with the second-ranked Sooners and being such a huge part of their success that he finished second in the Heisman Trophy voting and already is getting asked about turning professional.
And yet, that is where Peterson sits today at all of 19 years old.
"When I came in, I knew what kind of program I was coming into and the group of guys I was playing with, so I wouldn't say I'm surprised," he said. "I knew we came to play hard, bust our butts and just get out there and win games, and we'd be here."
Peterson says that without the slightest bit of arrogance. In fact, getting him to answer questions is nearly as difficult as tackling him. For all his power and explosiveness on the field, Peterson is shy and soft-spoken off it.
So let his numbers do the talking.
Peterson rushed for 1,843 yards and 15 touchdowns and had 11 100-plus-yard rushing games, an NCAA freshman record. He is 54 yards shy of Billy Sims' single-season Oklahoma rushing record and 21 from passing former Wisconsin tailback Ron Dayne's freshman rushing record.
Oh, and his second-place finish in the Heisman balloting behind Southern Cal quarterback Matt Leinart is the best ever for a freshman. He finished ahead of his own quarterback, Jason White, who won last season.
Peterson's best performances have come in big games. He had more than 200 yards in victories over Texas and Oklahoma State. He added 172 yards and three touchdowns in the Big 12 title game victory over Colorado.
"I have never seen a guy that big, that strong, that fast," Colorado coach Gary Barnett said after the game.
Peterson, who is 6 feet 2 and 210 pounds, was a highly regarded recruit coveted by many schools. He said his final choices came down to Oklahoma, USC, Texas and Miami. One thing that impressed him about Oklahoma: "They told me they would win with or without me," he said. "They said, "If you come here, you can help us do it. If not, we're still going to win.' That stuck with me."
To a man, Peterson's teammates say they were amazed how ready he was for college football. He arrived in Norman last summer and was already up to the physical challenge. Wide receiver Mark Clayton said Peterson showed up in "amazing" condition. And he didn't figure that to be the case.
"We had high expectations for him," Clayton said. "But college is nothing like high school, workouts are totally different, the games are totally different. So we were like, "Wait until he gets here, then he'll see how it really is.' We all looked forward to seeing that first workout, seeing him throw up and whine about it, but he never did that."
Once on the field, linemen learned just how beautiful it is to block for Peterson.
"Instead of blocking for five seconds, all I have to do is block for a half-second and he was out of there," Jammal Brown said.
All this success occurred after he was injured early in fall practice. On the third play of the first full-squad scrimmage, Peterson injured his shoulder, hindering him for the rest of camp. Still, he rushed for 100 yards in his first game. The only game he failed to top 100 was against Nebraska, when he did not start after being hurt in the previous game.
"Did we really know? I can't say that we did," OU coach Bob Stoops said. "We felt he was still awfully special when you watched the way he ran through practice and worked. But when he had that injury you wondered if he would be able to do it this year and be able to pick everything up.
"I think it's probably even more remarkable what he did this whole season when you look at how much practice time he missed after the injury and two-a-days after the scrimmage."
Peterson managed to find some good in that injury, too.
"It kind of helped me, in a way," he said. "I got to sit back and watch what was going on and learn."
Peterson admits all the attention, especially the adulation in Oklahoma, can be a bit overwhelming. But he does have the perspective offered by some harrowing life experiences. At age 7, his older brother, Brian, was killed riding a bike when a drunk driver sped through a school zone. At age 14, he was dealt another blow when his father, Nelson Peterson, was convicted of laundering money from the sale of crack cocaine. He was sentenced to 10 years in prison and is at a federal correctional institute in Texarkana, Texas.
Peterson speaks often with his father from prison; they talked last week. "He's been telling me to go out there and practice hard, which he knows I do anyway," Adrian said.
Nelson Peterson is not scheduled for release until 2007. By then, Adrian, the son he nicknamed "AD" _ short for All Day, as in how long Peterson can run _ might have a Heisman Trophy on his mantle and an NFL signing bonus in the bank.
And, given what he has so quickly accomplished, none of it would be a surprise.