"Me and O.J. have been friends since Pampers," said Walker, who grew up in Huntington, W.Va., a few blocks from Mayo, his best basketball buddy.
As boys, they played against each other from the time they could dribble until joining forces at age 9. They played on the same traveling team and even attended the same out-of-state high school, Cincinnati's North College Hill, where they combined to win two state titles.
"We're basically the same person," Mayo said.
But when the going got tough last summer and the Ohio High School Athletic Assn. ruled that Walker had exhausted his athletic eligibility, the tough got going -- Mayo to his hometown Huntington High and Walker to Kansas State, a year earlier than expected.
Their increasingly winding road takes another unforeseen turn today. It will be Walker's new team versus Mayo's future team when Kansas State (8-3) plays USC (9-2) in the Las Vegas Classic at the Orleans Arena in Las Vegas. Mayo, a point guard regarded as one of the top high school seniors in the country, signed a letter of intent with USC last month.
"We considered going to the same place," Walker said of his college decision, "but due to my circumstances, I had to do what was best for me. That's where we're at now."
After learning that he could no longer play at North College Hill, Walker completed his high school coursework and enrolled at Kansas State as a part-time student in November. But the freshman couldn't join the Wildcats until last week, when he went from his first practice to his first game to his first start in a span of four days.
"Everything's been pretty fast," Walker said. "Right now, I'm going pretty good for a person that's not in shape and only practiced a couple of times with the team."
The 6-foot-6 forward scored 15 points off the bench in his debut against Kennesaw State (Ga.) on Sunday and followed that with 11 points as a starter against Maryland Eastern Shore on Tuesday. He's shooting 50% from the field and averaging 20 minutes a game, though he's still clearly far from a finished product.
"He was tentative because he didn't know what he was doing and we had to limit a lot of his stuff," Kansas State Coach Bob Huggins said. "Hopefully by [today] we can get him caught up."
USC Coach Tim Floyd had a more glowing assessment of Walker's impact.
"All I know is that Wichita State is the eighth-ranked team in the country and they beat Kennesaw by nine and Kansas State beat them by 28 with Walker in the lineup," Floyd said. "So apparently he makes them a lot better."
Floyd had hoped to land both Mayo and Walker early in the recruiting process "because they had been together for so long, but it didn't work out."
When Mayo landed in Los Angeles for his official visit in November, one of his first calls was to Walker.
"We conversate every day," Mayo said at the time.
The friends believe that dialing long distance could be more beneficial to their careers than talking to each other across the same basketball court, at least for the next year or so.
"Us separating, it will give him an opportunity to market himself even more and learn how to run a team and be the captain of a team," Mayo said. "Bill is probably the most talented player in the country, as far as what he can do and the way he can get off the ground and his attitude toward the game. He can change the game in a lot of different ways."
Said Walker: "Hopefully, if we play this right we can all be in the NBA together."
Though he is a college freshman and has already turned 19, Walker cannot make himself available for the NBA draft until 2008 because his original high school class will not graduate until this spring, according to league spokesman Tim Frank. Walker said he's not concerned with his draft status, only making himself the best player possible by the time he's eligible to turn pro.
Walker learned a lesson in humility Tuesday when teammate Cartier Martin surrendered his spot in the starting lineup to better integrate Walker into the flow of Kansas State's schemes.
"That's the biggest thing right now, getting him game-ready," said Martin, the Wildcats' leading scorer. "Being in shape and being game-ready are totally different. We need to get him on the floor and get his feet under him."
Said Huggins: "He's got a really high basketball IQ. We've just got to get him in game shape."
A gifted slasher who has an enviable combination of size and quickness, Walker was showered with ovations in each of his first two games in Manhattan, Kan. One of the biggest broke out when Walker relayed his Christmas wish via a message on the video scoreboard: winning a national title.
"All you've got to do is get into March," Walker said. "Once you get into March, anything can happen."
For the first time, he'll have to do it without his marching partner.